Rice Ratoon Crop: A Sustainable Rice Production System for Tropical Hill Agriculture
Institute of Biological Sciences, Faculty of Science, University of Malaya, Kuala Lumpur 50603, Malaysia
*
Author to whom correspondence should be addressed.
Sustainability 2014, 6(9), 5785-5800; https://doi.org/10.3390/su6095785
Submission received: 11 March 2014
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Revised: 15 July 2014
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Accepted: 24 July 2014
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Published: 29 August 2014
(This article belongs to the Section Sustainable Agriculture)
Abstract
:Increasing and sustainable production of rice in tropical hill area is facing various problems where rice ratooning can overcome the limitations. In this study; 22 rice entries were transplanted into experimental tank placed in the hill slope following Completely Randomized Design with five replications to asses’ agronomic performance of main crop and ratoon crop where Entry 13 demonstrated highest grain yield per plant (42.06 ± 1.2 gm) as main crop, as well as ratoon crop (3.37 ± 0.28 gm); Entry 19 produced lowest grain yield per plant (5.01 ± 0.31 gm) as main crop and Entry 31 as ratoon crop (0.47 ± 0.03 gm). The grain yield per plant of both the main and ratoon crop demonstrated significant (** at 5% level and *** at 1% level) positive correlation with number of tiller per plant (0.64 ** and 0.52); number of fertile tiller per plant (0.66 ** and 0.63 **); grain per panicle (0.72 ** and 0.53); fertile grain per panicle (0.80 *** and 0.63) and thousand-grain weight (0.66 ** and 0.54). The Duncan Multiple Range test and Analysis of Variance also confirmed the different grouping and significant differences of productivity and agronomic performances of the entries. The information of this investigation will helps the rice breeder as well as marginal rice farmers to consider rice ratooning as an important practice for sustainable rice production in tropical agriculture system for maximum gains.
1. Introduction
Rice is a main staple food for human consumption all over the world. The people who live in the tropical hill area, such as Malaysian people, also consume rice based dishes but the production of rice in this area is insufficient (currently 72% [1]). Thus, Malaysia imports rice from different counties, such as Thailand, Vietnam, Pakistan, and India, every year [2]. The Malaysian Government has taken several initiatives in the 3rd to 7th Malaysian Plans (3 MP–7 MP) to increase rice production [2], hence, the productivity increased from 2.1 ton/ha to 3.6 ton/ha from 1961 to 2008 [1]. However, the land area for rice cultivation remained constant at 0.7 million hectares since 1980 [1]. Due to some agro-ecological constraints it is difficult to increase rice cultivation area in Malaysia, so increasing production per unit area is the only way to achieve sustainable rice production [3]. The American Society of Agronomy [4] and United States Congress [5] have defined sustainable agriculture and mentioned five important parts, such as emphasizing productivity, improving environmental quality, efficient use of non-renewable resources, enhancing economic viability, and upgrading the quality of life. In these circumstances, ratooning of rice can be a good solution for intensifying and sustainable rice production [6] in hill regions. Rice ratooning is not a new cultivation practice for rice breeding because many countries (USA, Brazil, Japan, India, Philippines, Thailand, and Taiwan) of the world have already adopted this system [7]. Moreover, the Dominican Republic and USA are using rice ratooning on a commercial scale. Malaysian tropical hill areas, where heavy rainfall and high temperature are sustained all year are suitable for ratoon rice cultivation under rain-fed conditions [7]. Ratoon rice grows 65% earlier than main crops and requires 50% to 60% less labor. The production cost is also lower than main crops due to the minimized cost for land preparation, transplantation, and crop maintenance. Ratooning requires a short duration, and yield is up to 50% of main crops, which increase the opportunity for cropping intensity per unit of cultivated area [8,9].
During previous research (from 2009 to 2011), while screening the best parental lines for aroma and kernel elongation among 53 aromatic rice lines, stubbles from different lines demonstrated good ratoon performance (Visual estimation) [10], which inspired a detailed study of their potentiality as sustainable ratoon rice crop production. Based on this preliminary information, in the present investigation, performance of agronomic characters, such as number of tillers per hill, number of fertile tillers per hill, number of days to flowering, grain filling periods, number of days to maturity, plant height, panicle length, grains per panicle, fertile grains per panicle, thousand-grain weight, and grain yield per plant, of 22 rice entries, and their ratoon were evaluated to assess the possibility of using rice ratoon crops for the rising production of rice in Malaysian tropical hill areas.
2. Materials and Methods
A total of 22 rice entries (Oryza sativa subsp. indica) were collected from International Centre for Tropical Agriculture (CIAT, Cali, Colombia), International Rice Research Institute (IRRI, Los Baños, Laguna, Philippines), West African Rice Development Association (WARDA, Cotonou, Benin), International Institute of Tropical Agriculture (IITA, Ibadan, Oyo State, Nigeria), and Senegal, Mayanmar and Argentina (Table 1), for conducting experiment at the experimental field (hill slope) of the Institute of Biological Sciences, University of Malaya, Malaysia, from June 2013 to December 2013. The experiment was laid out in a Completely Randomized Design (CRD) with five replications for main and ratoon crops. Before planting, seeds of the selected genotypes were sown in small pots containing 500 gm black soil. After 3 weeks, seedlings were transplanted into experimental tank (75 × 100 × 75 cm) filled with loam soil and 100 gm NPKS (15:15:15:2) as recommended by Chatterjee and Maiti [11], at the rate of two seedlings per hill with row to row distance of 25 cm and plant to plant distance of 20 cm. Intercultural operations, i.e., weeding, water management, and plant protection measures were followed for normal growth of main crop [12].
| Entry | Designation | Cross | Origin |
|---|---|---|---|
| E1 | (88023-RE) | Unknown | CIAT |
| E2 | (CT9882-16-4-2-3-2P-M) | Unknown | CIAT |
| E3 | (H013-5-3-B4) | Unknown | ARGENTINA |
| E4 | (H014-1-1-B2) | Unknown | ARGENTINA |
| E8 | (IR 77736-54-3-1-2) | NSIC RC 148/PSB RC 64//NSIC RC 148 | IRRI |
| E9 | (IR 78006-55-2-3-3) | IR 67406-6-3-2-3/IR 72860-80-3-3-3 | IRRI |
| E11 | (IR 78554-145-1-3-2) | IR 72861-13-2-1-2/IR 68450-36-3-2-2-3 | IRRI |
| E12 | (IR 77298-14-1-2) | IR 64 (WH)/ADAY SEL//3*IR64 | IRRI |
| E13 | (IR 77512-2-1-2-2) | IR 68726-3-3-1-2/IR 71730-51-2 | IRRI |
| E14 | (IR 77629-72-2-1-3) | IR 71730-51-2/IR 71742-267-3-2 | IRRI |
| E15 | (M1-10-29 UL) | Unknown | MYANMAR |
| E16 | (TOX 3226-5-2-2-2-2) | ITA 235/IR 9828-91-2-3//CT 19 | IITA |
| E18 | (WAB 272-B-B-5-H5) | 3290/WASC165 | WARDA |
| E19 | (WAB 99-84) | ITA257/WABUKA | WARDA |
| E20 | (WAB 337-B-B-15-H1) | ITA 135/WABC 165 | WARDA |
| E21 | (WAB 515-B-10 A 1-4) | Unknown | WARDA |
| E22 | (WAS 169-B-B-4-2-7) | Jaya/Basmati 370 | SENEGAL |
| E25 | (WAS 197-B-4-1-25) | IR 31851-96-2-3-2-1/IR 66231-37-1-2 | SENEGAL |
| E31 | (WAS 197-B-6-3-4) | IR 31851-96-2-3-2-1/IR 66231-37-1-2 | SENEGAL |
| E32 | (WITA 7 = TOX 3440-171-1-1-1-1) | TOX891-212-1-201-1-105/TOX3056-5-1 | WARDA |
| E35 | (IR 64) | IR 5657-33-2-1/IR 2061-465-1-5-5 | IRRI |
| E37 | (PSB RC2= IR 32809-26-3-3) | IR 4215-301-2-2-6/BG90-2//IR 19661-131-1-2 | IRRI |
The hills (5 hills excluding the border hills) were randomly selected from each unit block for pre- and post-harvest data, such as number of tiller per hill, number of fertile tiller per hill, number of days to flowering, grain filling periods, number of days to maturity, plant height (cm), panicle length (cm), grains per panicle, fertile grains per panicle, thousand-grain weight (gm), and grain yield per plant (gm) [13]. The main crop was harvested, leaving a stubble height of 20 cm above ground level [14] and allowed for ratooning. No intercultural operations (weeding, insecticide, and fertilizer) were done for ratoon crops, and after maturity, five hills were selected for pre- and post-harvest data collection. Collected data were analyzed with SAS Version 9.2 [15] for descriptive statistical analysis (Mean and Stander Error of Mean), where the mean differences were adjudged with Duncan’s Multiple Range Test (DMRT), Analysis of Variance (ANOVA), and trait correlation analysis.
3. Results
The performances (Mean value with Standard error of mean) of agronomic traits (Number of tillers per hill, number of fertile tillers per hill, days to flowering, grain filling periods, days to maturity, plant height, panicle length, grains per panicle, fertile grains per panicle, thousand-grain weight, and grain yield per plant) of the selected 22 entries were different for main crop and in ratoon crop. The maximum and minimum mean values of the traits were demonstrated by different entries which observed in different significance level (Table 2 and Table 3) by Analysis of Variance (ANOVA), different groups (Table 4 and Table 5) by Duncan Multiple Range Test (DMRT), and different type of correlation (Table 6 and Table 7).
3.1. Number of Tillers per Hill
In the present investigation, the total number of tillers in the main crop was different for the entries, where Entry 13 and Entry 15 demonstrated maximum tiller number per hill (26.6 ± 0.68, 26.6 ± 0.75) and Entry 19 produced minimum tiller number per hill (7.8 ± 0.58). For the number of tillers per hill, Entry 13 and Entry 15 fall in the same group (Group a) while Entry 19 fall in the different group (Group l) by DMRT. There were significant differences between the replication (6.91 ***) and between the Entry (76.83 ***) in the main crop. The number of tillers per hill demonstrated significant positive correlation with number of fertile tillers per hill (0.97 ***) and grain yield per plant (0.64 **) while there was a negative correlation with plant height (−0.54). Previously many researchers [16,17,18] mentioned that number of tillers per hill has positive effects on yield.
For the ratoon crop, the maximum number of tiller per hill was observed in Entry 35 (17.2 ± 0.73) and minimum number of tiller per hill in Entry 19 (4.4 ± 0.40). DMRT also confirmed the position in different group of Entry 19 (Group l) and Entry 35 (Group a). The replications were significantly different (6.86 ***) with the different entries (47.83 ***) for number of ratoon tiller per hill in ratoon crop. The number of ratoon tiller per hill represented significant positive correlation with number of fertile ratoon tiller per hill (0.93 ***) but did not show negative correlation with any of the traits.
3.2. Number of Fertile Tillers per Hill
The maximum number of fertile tillers per hill for main crop was observed in Entry 13 (24.2 ± 0.80), which was positioned in Group a (DMRT), and minimum number of fertile tillers per hill was in Entry 19 (5.4 ± 0.51) and was placed in Group j (DMRT). The replications (7.85 ***) and the Entry (52.18 ***) was significantly different and the number of fertile tillers per hill demonstrated significant positive correlation with grain yield per plant (0.66 **) while negative correlation with plant height (−0.57).
In case of the ratoon crop, the maximum number of fertile tillers per hill was observed in Entry 13 (15.2 ± 0.37) and minimum number of tiller per hill in Entry 19 (3.0 ± 0.32). DMRT also confirmed the position in different group of Entry 13 (Group a) and Entry 19 (Group i). The replications were significantly different (5.91 ***) with the different entries (35.34 ***) for number of fertile ratoon tillers per hill. The number of fertile ratoon tillers per hill is the most important trait for higher grain yield in ratoon crop, which represented positive correlation with all the traits.
| Source | No. of Tiller/Hill | No. of Fertile Tiller/Hill | Days to Flowering | Grain Filling Periods | Days to Maturity | Plant Height (cm) | Panicle Length | Grain/ Panicle | Fertile Grain/Panicle | Thousand Grain Weight (gm) | Grain Yield/Plant (gm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Replication | 6.91 *** | 7.85 *** | 1.97 NS | 3.29 ** | 0.41 NS | 0.74 NS | 2.37 NS | 2.10 NS | 1.58 NS | 3.48 ** | 5.32 *** |
| Variety | 76.83 *** | 52.18 *** | 141.67 *** | 9.38 *** | 160.95 *** | 189.45 *** | 20.37 *** | 67.15 *** | 76.97 *** | 76.63 *** | 82.69 *** |
Note: The F values represented by NS = Non-significant, ** = Significant at 5% level and *** = Significant at 1% level.
| Source | No. of Tiller/Hill | No. of Fertile Tiller/Hill | Days to Flowering | Grain Filling Periods | Days to Maturity | Plant Height (cm) | Panicle Length | Grain/ Panicle | Fertile Grain/Panicle | Thousand Grain Weight (gm) | Grain Yield/Plant (gm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Replication | 6.86 *** | 5.91 *** | 3.11 ** | 0.37 NS | 2.31 NS | 0.78 NS | 1.42 NS | 0.27 NS | 1.17 NS | 2.64 ** | 1.10 NS |
| Variety | 47.83 *** | 35.34 *** | 425.32 *** | 22.25 *** | 470.20 *** | 108.38 *** | 39.68 *** | 15.10 *** | 27.18 *** | 73.35 *** | 30.14 *** |
Note: The F values represented by NS = Non-significant, ** = Significant at 5% level and *** = Significant at 1% level.
| Genotypes | No. of Tiller/Hill | No. of Fertile Tiller/Hill | Days to Flowering | Grain Filling Periods | Days to Maturity | Plant Height (cm) | Panicle Length | Grain/ Panicle | Fertile Grain/Panicle | Thousand Grain Weight (gm) | Grain Yield/Plant (gm) |
|---|---|---|---|---|---|---|---|---|---|---|---|
| E1 | 16.2 gf | 15.4 cde | 82.4 h | 6.8 cdefgh | 103.6 efg | 68.0 j | 15.8 hi | 64.2 ghi | 54.6 f | 17.5 h | 14.1 ij |
| E2 | 18.0 ef | 16.2 bcd | 91.2 ef | 7.8 bc | 115.8 a | 73.4 h | 20.4 cde | 142.6 a | 98.2 a | 19.3 fg | 29.4 d |
| E3 | 15.2 gh | 13.8 efg | 92.4 de | 7.6 bcd | 114.2 bc | 83.8 cd | 21.2 bcd | 113.0 b | 91.8 b | 30.0 a | 34.0 c |
| E4 | 11.8 jk | 10.4 hi | 86.0 g | 6.4 defgh | 113.6 bc | 77.6 ef | 16.2 ghi | 108.4 b | 83.8 c | 29.3 a | 24.7 e |
| E8 | 16.2 gf | 12.8 fg | 79.4 i | 7.8 bc | 97.6 h | 87.8 b | 15.4 i | 62.8 hij | 50.6 fg | 21.5 de | 14.8 hij |
| E9 | 12.0 jk | 9.8 i | 87.2 g | 11.0 a | 115.2 ab | 72.6 h | 22.8 b | 55.6 ijkl | 46.2 ghi | 14.0 i | 6.9 l |
| E11 | 24.8 b | 22.4 a | 85.8 g | 5.8 gh | 104.4 def | 64.2 k | 16.6 ghi | 66.6 fgh | 48.4 fg | 15.2 i | 17.6 ghi |
| E12 | 20.2 d | 16.8 bcd | 85.8 g | 5.6 h | 104.6 def | 73.2 h | 20.2 cde | 92.2 c | 83.8 c | 26.4 bc | 38.0 b |
| E13 | 26.6 a | 24.2 a | 95.4 c | 6.8 cdefgh | 113.0 c | 79.2 e | 21.2 bcd | 77.8 de | 64.6 e | 27.2 b | 42.1 a |
| E14 | 22.0 c | 17.8 b | 86.8 g | 8.0 bc | 104.8 de | 70.6 i | 22.0 bc | 63.8 ghi | 47.8 fgh | 21.0 de | 17.8 gh |
| E15 | 26.6 a | 23.4 a | 81.0 hi | 6.2 efgh | 93.8 i | 72.8 h | 17.6 fgh | 60.4 hijk | 48.6 fg | 19.3 fg | 21.5 ef |
| E16 | 13.8 hi | 12.0 gh | 103.2 a | 8.2 b | 116.2 a | 85.0 c | 25.4 a | 72.6 efg | 60.8 e | 17.3 h | 12.9 jk |
| E18 | 13.0 ij | 10.6 hi | 81.0 hi | 7.4 bcde | 103.2 efg | 76.0 fg | 19.0 ef | 52.8 kl | 44.6 ghij | 21.1 de | 10.5 k |
| E19 | 7.8 l | 5.4 j | 90.4 f | 6.0 fgh | 105.4 d | 84.8 c | 20.3 cde | 46.4 l | 35.6 k | 20.5 ef | 5.0 l |
| E20 | 11.0 k | 7.2 j | 80.6 i | 7.2 bcdef | 103.0 fg | 96.0 a | 21.8 bc | 50.2 l | 40.4 ijk | 18.7 gh | 5.6 l |
| E21 | 8.6 l | 6.8 j | 86.0 g | 7.0 bcdefg | 102.4 g | 96.0 a | 17.8 fg | 53.8 jkl | 38.6 jk | 21.4 de | 5.4 l |
| E22 | 11.4 jk | 9.4 i | 85.8 g | 7.0 bcdefg | 104.0 defg | 88.0 b | 15.8 hi | 47.8 l | 37.2 k | 21.8 de | 6.7 l |
| E25 | 17.2 ef | 15.4 cde | 93.4 d | 7.4 bcde | 112.6 c | 68.6 j | 17.0 ghi | 53.0 kl | 41.4 hijk | 22.4 d | 15.7 ghij |
| E31 | 14.0 hi | 12.4 gh | 95.6 c | 7.0 bcdefg | 113.8 bc | 73.4 h | 19.1 ef | 49.4 l | 35.8 k | 15.1 i | 6.8 l |
| E32 | 16.4 gf | 14.8 def | 101.4 b | 6.2 efgh | 113.6 bc | 82.2 d | 17.8 fg | 85.8 cd | 72.4 d | 22.4 d | 23.2 e |
| E35 | 19.0 de | 17.6 bc | 85.8 g | 7.2 bcdef | 114.0 bc | 75.6 g | 20.7 cde | 61.6 hijk | 49.4 fg | 20.9 de | 18.5 fg |
| E37 | 17.6 ef | 15.2 de | 93.2 d | 8.2 b | 115.0 ab | 62.6 k | 19.4 def | 75.4 ef | 61.2 e | 25.0 c | 23.3 e |
Note: Means with the same letter are not significantly different at 5% level.
| Genotypes | No. of Tiller/Hill | No. of Fertile Tiller/Hill | Days to Flowering | Grain Filling Periods | Days to Maturity | Plant Height (cm) | Panicle Length | Grain/ Panicle | Fertile Grain/Panicle | Thousand Grain Weight (gm) | Grain Yield/Plant (gm) | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| E1 | 9.8 def | 7.0 de | 35.8 b | 3.0 gh | 46.0 b | 20.8 cd | 11.7 abc | 9.2 hi | 5.6 cdefg | 7.5 l | 0.6 cd | |
| E2 | 0.0 m | 0.0 j | 0.0 k | 0.0 i | 0.0 k | 0.0 i | 0.0 g | 0.0 j | 0.0 h | 0.0 m | 0.0 e | |
| E3 | 9.0 efg | 6.0 efg | 37.6 a | 3.6 fgh | 47.6 a | 24.2 b | 12.3 ab | 11.2 fghi | 7.0 c | 14.9 bc | 0.6 cd | |
| E4 | 8.0 fgh | 6.0 efg | 25.6 d | 5.0 cd | 35.6 de | 21.2 cd | 11.5 abc | 9.2 hi | 6.0 cdef | 19.3 a | 1.2 b | |
| E8 | 11.2 cd | 6.6 ef | 25.4 de | 4.4 cdef | 34.6 efgh | 19.4 d | 10.6 cd | 20.8 a | 14.8 a | 11.9 efgh | 1.4 b | |
| E9 | 7.6 ghi | 5.2 efgh | 24.2 fg | 3.6 fgh | 34.8 defg | 17.0 e | 11.1 bcd | 11.4 efghi | 4.6 defg | 7.2 l | 0.6 cd | |
| E11 | 13.0 c | 8.6 cd | 28.2 c | 6.0 b | 40.0 c | 13.6 f | 9.1 e | 12.6 cdefgh | 6.2 cde | 10.6 hi | 0.6 cd | |
| E12 | 13.0 c | 9.4 c | 24.2 fg | 2.6 h | 34.6 efgh | 23.8 b | 10.8 bcd | 12.4 cdefgh | 5.4 cdefg | 8.6 kl | 0.7 cd | |
| E13 | 16.4 ab | 15.2 a | 24.8 def | 3.4 fgh | 33.0 i | 23.6 b | 12.7 a | 18.2 ab | 11.4 b | 16.1 b | 3.4 a | |
| E14 | 10.6 de | 6.6 ef | 22.2 h | 4.0 efg | 34.6 efgh | 19.4 d | 11.5 abc | 12.0 defgh | 6.4 cd | 9.1 jk | 0.7 cd | |
| E15 | 9.2 efg | 6.4 ef | 25.4 de | 5.0 cd | 36.0 d | 20.6 cd | 11.4 abc | 15.0 cd | 6.2 cde | 12.1 efgh | 0.8 cd | |
| E16 | 5.4 kl | 3.8 hi | 28.2 c | 7.2 a | 41.0 c | 10.6 g | 7.1 f | 8.6 i | 4.0 g | 7.5 l | 0.6 cd | |
| E18 | 5.6 jkl | 3.6 hi | 21.2 hi | 5.2 bc | 34.6 efgh | 33.4 a | 11.9 abc | 14.8 cde | 6.8 c | 13.7 cd | 0.6 cd | |
| E19 | 4.4 l | 3.0 i | 24.6 def | 4.8 cde | 34.2 fghi | 23.6 b | 12.8 a | 10.2 ghi | 4.6 defg | 10.1 ij | 0.5 cd | |
| E20 | 5.4 kl | 3.6 hi | 23.4 g | 3.6 fgh | 33.4 hi | 21.4 cd | 11.6 abc | 14.0 cdef | 6.4 cd | 12.7 def | 0.7 cd | |
| E21 | 7.4 ghij | 5.0 fgh | 25.4 de | 3.6 fgh | 34.2 fghi | 22.2 bc | 11.6 abc | 12.2 cdefgh | 4.8 defg | 11.2 ghi | 0.6 cd | |
| E22 | 10.0 de | 6.2 efg | 20.8 i | 3.4 fgh | 33.6 ghi | 13.6 f | 6.9 f | 12.0 defgh | 4.2 fg | 8.1 kl | 0.6 cd | |
| E25 | 12.4 c | 9.2 c | 24.4 efg | 4.2 def | 35.4 def | 21.0 cd | 9.9 de | 15.6 bc | 6.0 cdef | 12.2 efg | 0.8 cd | |
| E31 | 6.8 hijk | 4.4 ghi | 24.8 def | 3.6 fgh | 35.0 def | 16.2 e | 11.4 abc | 12.8 cdefg | 4.6 defg | 9.1 jk | 0.5 d | |
| E32 | 6.0 ijkl | 4.0 hi | 24.4 efg | 3.4 fgh | 34.4 efgh | 12.8 f | 9.1 e | 11.6 defghi | 4.2 fg | 8.5 kl | 0.9 c | |
| E35 | 17.2 a | 12.2 b | 21.6 hi | 6.0 b | 34.4 efgh | 13.4 f | 9.1 e | 12.2 cdefgh | 4.4 efg | 11.4 fghi | 0.8 cd | |
| E37 | 15.2 b | 13.4 b | 16.0 j | 4.8 cde | 31.6 j | 8.0 h | 6.7 f | 15.0 cd | 4.6 defg | 13.0 de | 1.3 b | |
Note: Means with the same letter are not significantly different at 5% level and Entry 2 did not produce ratoon tiller.
| Traits | No. of Tiller/Hill | No. of Fertile Tiller/Hill | Days to Flowering | Grain Filling Periods | Days to Maturity | Plant Height (cm) | Panicle Length | Grain/ Panicle | Fertile Grain/Panicle | Thousand Grain Weight (gm) |
|---|---|---|---|---|---|---|---|---|---|---|
| No. of Fertile Tiller/Hill | 0.97 *** | |||||||||
| Days to Flowering | 0.02 | 0.08 | ||||||||
| Grain Filling Periods | 0.18 | 0.20 | 0.06 | |||||||
| Days to Maturity | 0.11 | 0.03 | 0.74 *** | 0.30 | ||||||
| Plant Height (cm) | 0.54 | 0.57 | 0.05 | 0.04 | 0.21 | |||||
| Panicle Length | 0.01 | 0.03 | 0.39 | 0.36 | 0.40 | 0.10 | ||||
| Grain/Panicle | 0.21 | 0.25 | 0.25 | 0.02 | 0.42 | 0.15 | 0.12 | |||
| Fertile Grain/Panicle | 0.23 | 0.27 | 0.27 | 0.06 | 0.41 | 0.15 | 0.15 | 0.95 *** | ||
| Thousand Grain Weight (gm) | 0.07 | 0.08 | 0.09 | 0.23 | 0.14 | 0.12 | 0.06 | 0.47 | 0.56 | |
| Grain Yield/Plant (gm) | 0.64 ** | 0.66 ** | 0.23 | 0.20 | 0.25 | 0.29 | 0.11 | 0.72 ** | 0.80 *** | 0.66 ** |
Note: ** = Significant at 5% level and *** = Significant at 1% level.
| Traits | No. of Tiller/Hill | No. of Fertile Tiller/Hill | Days to Flowering | Grain Filling Periods | Days to Maturity | Plant Height (cm) | Panicle Length | Grain/ Panicle | Fertile Grain/Panicle | Thousand Grain Weight (gm) |
|---|---|---|---|---|---|---|---|---|---|---|
| No. of Fertile Tiller/Hill | 0.93 *** | |||||||||
| Days to Flowering | 0.26 | 0.17 | ||||||||
| Grain Filling Periods | 0.28 | 0.22 | 0.38 | |||||||
| Days to Maturity | 0.37 | 0.27 | 0.95 *** | 0.53 | ||||||
| Plant Height (cm) | 0.11 | 0.07 | 0.56 | 0.17 | 0.54 | |||||
| Panicle Length | 0.25 | 0.21 | 0.71 ** | 0.25 | 0.70 ** | 0.81 *** | ||||
| Grain/Panicle | 0.52 | 0.50 | 0.33 | 0.30 | 0.41 | 0.43 | 0.52 | |||
| Fertile Grain/Panicle | 0.41 | 0.36 | 0.39 | 0.18 | 0.36 | 0.48 | 0.49 | 0.72 ** | ||
| Thousand Grain Weight (gm) | 0.43 | 0.44 | 0.45 | 0.42 | 0.49 | 0.58 | 0.59 | 0.53 | 0.56 | |
| Grain Yield/Plant (gm) | 0.52 | 0.63 ** | 0.13 | 0.08 | 0.13 | 0.21 | 0.29 | 0.53 | 0.63 ** | 0.54 |
Note: ** = Significant at 5% level and *** = Significant at 1% level.
3.3. Days to Flowering
The range of days to flowering was 79.4 ± 1.36 (Entry 8) to 103.2 ± 0.37 (Entry 16) for the main crop, while, for the ratoon crop, it was 16.0 ± 0.45 (Entry 37) to 37.6 ± 0.25 (Entry 3). The DMRT represented the similar group (Group a) for main crop (Entry 16) and ratoon crop (Entry 3) while different groups for the main crop (Entry 8, Group i) and ratoon crop (Entry 37, Group j). The differences of replications of the main crop were non-significant (1.97 NS) while for the ratoon crop, it was significantly different (3.11 **) but in both cases (main crop, 141.67 *** and ratoon crop, 425.32 ***) the entries was significantly different. For both crops (main and ratoon crop) the flowering days was positively correlated with all the studied traits but the flowering days of main crops demonstrated significant positive correlation with days to maturity (0.74 ***) while the flowering days of ratoon crop exhibited significant positive correlation with days to maturity (0.95 ***) and panicle length (0.71 **).
3.4. Grain Filling Periods
The grain filling periods for the main crop was 5.6 ± 0.25 (Entry 12) to 11.0 ± 0.45 (Entry 9), while, for the ratoon crop, it was 2.6 ± 0.25 (Entry 12) to 7.2 ± 0.37 (Entry 16). The Entry 9 of main crop and Entry 16 of ratoon crop was placed in the same group (Group a) while Entry 12 for both crop was in lowest group (Group h) for the lowest grain filling periods by DMRT. The replications for grain-filling periods were significantly different for main crop (3.29 **) but non-significantly differ (0.37 NS) for ratoon crop while the entries was significantly different in both (main crop, 9.38 *** and ratoon crop, 22.25 ***) crops. The grain filling periods of main crop was positively correlated with days to maturity (0.30) and panicle length (0.36) but negatively correlated with all other traits, while, for the ratoon crop, it was positively correlated with all studied.
3.5. Days to Maturity
The range of days to maturity was 93.8 ± 0.58 (Entry 15) to 116.2 ± 0.80 (Entry 16) for the main crop while for ratoon crop it was 31.6 ± 0.51 (Entry 37) to 47.6 ± 0.51 (Entry 3). The DMRT represented the similar group (Group a) for the main crop (Entry 16) and the ratoon crop (Entry 3) while different for groups from the main crop (Entry 15, Group i) and ratoon crop (Entry 37, Group j). The differences of replications of the main crop (0.41) and ratoon crop (2.31) were non-significant but, in both cases (main crop, 160.95 *** and ratoon crop, 470.20 ***), the entries was significantly different.
The days to maturity of main crop was negatively correlated with plant height (−0.21) and ratoon crop was positively correlated with plant height (0.54) and panicle length (0.70) while other traits was positively correlated with the days to maturity of main and ratoon crop.
3.6. Plant Height
The plant height of the main crop was maximum 96 cm for Entry 20 (96.0 ± 0.71) and Entry 21 (96.0 ± 0.45) while for ratoon crop it was 33.4 cm in Entry 18 (33.4 ± 0.51). The minimum plant height was observed 62.6 cm (62.6 ± 0.68) for main crop and 8 cm (8.0 ± 0.32) for ratoon crop in Entry 37. The DMRT represented same group (Group a) for Entry 20 and Entry 21 as main crop and Entry 18 as ratoon crop, while Entry 37 falls in a different group than the main crop (Group k) and ratoon crop (Group h). For main crop and ratoon crop, the replication difference was non-significant (0.74 NS and 0.78 NS) but the entries differences were significant (189.45 *** and 108.38 ***). Plant height was positively correlated with panicle length (0.10) and thousand-grain weight (0.12) but negatively correlated with other traits in main crop while it demonstrated positive correlation with all the studied traits in the ratoon crop.
3.7. Panicle Length
The panicle length of the main crop was 15.4 ± 0.68 (Entry 8) to 25.4 ± 0.51 cm (Entry 16) while, for ratoon crop, it was 6.7 ± 0.24 (Entry 37) to 12.8 ± 0.47 cm (Entry 19). The lowest panicle length (6.7 ± 0.24 cm) was observed in Entry 37 (Figure 1a) and the higher panicle length (12.7 ± 0.49 cm) were observed in Entry 13 (Figure 1b) while most of the entries demonstrated medium panicle length (10 to 11 cm) (Figure 1a).
Figure 1.
Different types of panicle length of ratoon crop: (a) shows ratoon rice panicles with different length and (b) demonstrate best panicle with grain and length.
Figure 1.
Different types of panicle length of ratoon crop: (a) shows ratoon rice panicles with different length and (b) demonstrate best panicle with grain and length.
The Entry 16 of main crop and Entry 19 of ratoon crop was placed in the same group (Group a) while Entry 8 of main crop fall in different group (Group i) and Entry 37 of ratoon crop in another group (Group f) by DMRT. The replications for panicle length were non-significantly different for main crop (2.37) and ratoon crop (1.42) while the entries was significantly different in both (main crop, 20.37 *** and ratoon crop, 39.68 ***) crops. The panicle length of main crop was negatively correlated with number of tillers per hill (−0.01), number of fertile tillers per hill (−0.03), and thousand-grain weight (−0.06), but positively correlated with all other traits, while for ratoon crop it was positively correlated with all studied traits and significantly positive correlation was observed days to flowering (0.71 **), days to maturity (0.70 **), and plant height (0.81 ***).
3.8. Grain per Panicle
The maximum number of grain per panicle for main crop was observed in Entry 2 (142.6 ± 6.76), which was positioned in Group a (DMRT), and minimum number of grain per panicle was in Entry 19 (46.4 ± 3.25) was placed in Group l (DMRT). The differences between replications (2.10) was non-significant but the entries (67.15 ***) was significantly different and the number of grain per panicle demonstrated significant positive correlation with fertile grain per panicle (0.95 ***) and grain yield per plant (0.72 **), while negative correlation with grain filling periods (−0.02) and plant height (−0.15).
For ratoon crop, the maximum number of grain per panicle was observed in Entry 8 (20.8 ± 1.07) and minimum number of grain per panicle in Entry 16 (8.6 ± 0.51). DMRT also confirmed the position in the different groups of Entry 8 (Group a) and Entry 16 (Group i). The replication differences were non-significant (0.27 NS), while significant differences were observed among the entries (15.10 ***). The number of grain per panicle represented significant positive correlation with fertile grain per panicle (0.72 **) and positive correlation with all other traits.
3.9. Fertile Grain per Panicle
The number of fertile grain per panicle was 35.6 ± 2.06 (Entry 19) to 98.2 ± 3.17 (Entry 2) for the main crop while for ratoon crop it was 4.0 ± 0.32 (Entry 16) to 14.8 ± 0.86 (Entry 8). The Entry 2 of main crop and Entry 8 of ratoon crop was placed in the same group (Group a) while Entry 19 of the main crop falls in different group (Group k) and Entry 16 of ratoon crop fall in another group (Group g) by DMRT. The replications for number of fertile grain per panicle was non-significantly differ for both the main (1.58 NS) and ratoon (1.17 NS) crop while the entries was significantly different in both (main crop, 76.97 *** and ratoon crop, 27.18 ***) crops. The number of fertile grain per panicle of main crop demonstrated significant positive correlation with grain per panicle (0.72 **) and grain yield per plant (0.80 ***), but negative correlation with number of tillers per plant (−0.23), grain filling periods (−0.06) and plant height (−0.15), while for ratoon crop it was positively correlated with all studied traits and significantly positive correlated with grain per panicle (0.72 **) and grain yield per plant (0.63 **).
3.10. Thousand Grain Weight
The thousand-grain weight of the main crop was 13.9 ± 0.49 (Entry 9) to 30.0 ± 1.02 gm (Entry 2) while for ratoon crop it was 7.2 ± 0.54 (Entry 9) to 19.3 ± 1.47 gm (Entry 4). The Entry 3 of main crop and Entry 4 of ratoon crop were placed in the same group (Group a) while Entry 9 falls in a different group than the main crop (Group i) and ratoon crop (Group l). The replications and entries for thousand-grain weight were significantly different for main crop (3.48 ** and 76.63 ***) and ratoon crop (2.64 ** and 73.35 ***). The thousand-grain weight was negatively correlated with grain filling periods (−0.23) and panicle length (−0.06) but positively correlated with all other traits for the main crop, while for ratoon crop it was positively correlated with all studied traits.
3.11. Grain Yield per Plant
The maximum grain yield per plant for main crop was observed in Entry 13 (42.1 ± 1.20 gm), which was positioned in Group a (DMRT) and minimum grain yield per plant was in Entry 19 (5.0 ± 0.31 gm) was placed in Group l (DMRT). The replications (5.32 ***) and the entries (82.69 ***) were significantly different. The grain yield per plant demonstrated significant positive correlation with number of tillers per hill (0.64 **), number of fertile tillers per hill (0.66 **), grain per panicle (0.72 **), fertile grain per panicle (0.80 ***) and thousand-grain weight (0.66 **) while negative correlation with grain filling periods (−0.20) and plant height (−0.29).
In case of the ratoon crop, the maximum grain yield per plant was observed in Entry 13 (3.4 ± 0.28 gm) and minimum grain yield per plant in Entry 31 (0.5 ± 0.03 gm). DMRT also confirmed the position in different group of Entry 13 (Group a) and Entry 31 (Group d). There were no significant differences among the replications (1.10 NS) but the entries were significantly different (30.14 ***) for grain yield per plant of ratoon crop. The grain yield per plant represented significant positive correlation with number of fertile tillers per hill (0.63 **) and fertile grain per panicle (0.63 **) while no negative correlation was observed with any of the trait.
4. Discussion
The average number of tillers per hill for main crop (16.34 ± 5.38) was reduced for the ratoon crop (9.70 ± 3.93) for all the studied entries which is similar to the observation of Maqsood et al. [19] while the average number of fertile tiller per hill for main crop (14.08 ± 5.29) also reduced in ratoon crop (6.92 ± 3.56) as the observation of Bollich and Turner [8], who mentioned that the ratoon crop produce less tiller than the main crop. The average days to flowering, grain filling periods and days to maturity for main crop (88.63 ± 6.50, 7.21 ± 1.36 and 108.35 ± 6.54) also shortened for ratoon crop (25.15 ± 4.62, 4.30 ± 1.28 and 36.12 ± 4.12), which is the same observation of Santos et al. [20] and Haque and Coffman [21], while Jones and Snyder [22] also mentioned that the ratoon rice needs very short growth duration usually 35% to 60% less than the main crop. The average plant height of the main crop (77.79 ± 9.17 cm) was greater than the average plant height of ratoon crop (19.04 ± 5.81 cm) which was previously mentioned by Zandstra and Samson [23], afterward Mengel and Wilson [24], while Jones [25] identified the less ability of using resources of ratoon plant. The average panicle length, grain per panicle and fertile grain per panicle of ratoon crop (10.52 ± 2.03 cm, 12.90 ± 3.56 and 6.10 ± 2.75) was less than the main crop (19.27 ± 2.84 cm, 70.74 ± 24.86 and 56.17 ± 18.95) as the statement of Evatt and Beachell [26], Akhgari et al. [27], and Birhane [28]. The average thousand-grain weight and grain yield per plant was higher in main crop (21.23 ± 4.37 gm and 17.92 ± 10.92 gm) than the ratoon crop (11.19 ± 3.20 gm and 0.87 ± 0.66 gm), while Kasturi and Purushothaman [29], Fageria et al. [30], Choi and Kwon [31], Hsieh and Young [32], and Szokolay [33] also observed the reduction of yield and yield related traits in ratoon crop.
Sadeghi [34] and Ranawake et al. [35] observed that the number of fertile tillers and number of grain per panicle had direct effect on grain yield per plant which also observed in the present investigation. The grain yield per plant was significantly and positively correlated with number of tiller per hill, number of fertile tiller per hill, grain per panicle, fertile grain per panicle and thousand-grain weight of both the main and ratoon crop. Ranawake et al. [35] observed negative correlation of plant height with thousand-grain weight but in the present study, both the main and ratoon crop demonstrated positive correlation of plant height with thousand-grain weight. Previously, Beser and Genctan [36], and later on Aide and Beighly [37] mentioned that plant height might be affected by plantation method, plant density and fertilizer application. Surek [38] and Ghosh et al. [39] mentioned that fertile tiller number and grain number per panicle affected by the environmental and cultivation factors which have great effect on grain yield while in this study, significant positive correlation of grain yield per plant was observed with most of the yield related traits in main and ratoon crop. Oad et al. [40] observed fewer effective tillers in ratoon crop compared to main crop, while Reddy and Pawar [41] observed lower performance of most of the traits in ratoon crop compared to the main crop which also observed in the present study. However, considering the cost, duration and management practice of rice ratoon crop, the production might be satisfactory for the marginal farmers of the hill region for using the same field within the short duration which will provide extra gain for sustainable rice production in tropical hill area.
5. Conclusions
Rice ratooning is not a new concept for the rice breeder, but evaluating high yielding main crop and ratoon crop variety has a great prospect for tropical hill agriculture. The marginal farmer of Malaysian hill area leave the field abandoned after harvesting the main crop and if they collect ratoon crop without any cultural practice, they can collect at least 8% grain Yield/Plant from Entry 13. In this experiment, for ratoon crop any intercultural operation such as weeding, pesticide and fertilizer did not follow to observe the real scenario of ratoon crop productivity at zero cost level. However, it is expected higher yield in good management practice, specially the vegetative and reproductive performance of Entry 13 ratoon’s can ensure higher yield. The Entry 13 can be a suitable rice variety as both main and ratoon crop for sustainable rice production in tropical agro-ecological environment.
Acknowledgments
The authors are deeply thankful to the International Rice Research Institute (IRRI, Los Baños, Laguna, Philippines), Malaysian Agricultural Research Development Institute (MARDI), International Centre for Tropical Agriculture (CIAT, Cali, Colombia), West African Rice Development Association (WARDA, Cotonou, Benin), International Institute of Tropical Agriculture (IITA, Ibadan, Oyo State, Nigeria), Senegal, Mayanmar and Argentina for providing research materials. They are also grateful to the Ministry of Higher Education Malaysia (MOHE) and University of Malaya, Kuala Lumpur for providing research facilities and grant (IPPP PV044-2011A) during these investigation.
Author Contributions
Golam Faruq has planed, analyzed results and helps to write this article as a supervisor. Rosna Mat Taha has advised, corrected and contributed to complete the experiment. Zakaria Hossain Prodhan participated in the research, collected data and did data analysis.
Conflicts of Interest
The authors declare no conflict of interest.
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Faruq, G.; Taha, R.M.; Prodhan, Z.H. Rice Ratoon Crop: A Sustainable Rice Production System for Tropical Hill Agriculture. Sustainability 2014, 6, 5785-5800. https://doi.org/10.3390/su6095785
AMA Style
Faruq G, Taha RM, Prodhan ZH. Rice Ratoon Crop: A Sustainable Rice Production System for Tropical Hill Agriculture. Sustainability. 2014; 6(9):5785-5800. https://doi.org/10.3390/su6095785
Chicago/Turabian StyleFaruq, Golam, Rosna Mat Taha, and Zakaria H. Prodhan. 2014. "Rice Ratoon Crop: A Sustainable Rice Production System for Tropical Hill Agriculture" Sustainability 6, no. 9: 5785-5800. https://doi.org/10.3390/su6095785
