Breeding Approaches for Controlled Conditions of Artificial Light Culture for Small Radish and Radish (Raphanus sativus L.)

Round 1

Reviewer 1 Report

The authors have prepared a manuscript concerning “Breeding approaches for controlled conditions of artificial light culture for small radish and radish (Raphanus sativus L.)”. I think some improvements are needed. Overall, the manuscript will meet the publishing standard of the journal after revisions.

Abstract: The description of the abstract part of the article is some longer, and it is recommended to reduce it to about 200 words.

Line 188-190: I suggest a more detailed description of the controlled conditions for plant growth.

Line 218: It is recommended to describe the indicators of each component and their measurement methods.

Line 448-451: “Another source of the ‘root diameter’ trait, cultivar ‘Octava’, was also characterized by 100% resistance to bolting and low pubescent leaves, which, however, were larger in size in comparison with cultivar ‘Viola’ (Table 3).” Here it is show that the ‘root diameter’ of ‘Octava’ is larger compared to ‘Viola’ and ‘Octava’, and it is recommended to add specific measured values for comparison when describing. The same is true elsewhere in the text.

Conclusions: The conclusion of the article is too lengthy, and it is recommended to reduce it to about 150 words.

Comments for author File: Comments.docx

Author Response

1. Abstract: The description of the abstract part of the article is some longer, and it is recommended to reduce it to about 200 words.

Response: We have reduced the abstract to 190 words, removing unnecessary details. As a result, the abstract is now on 11-23 lines instead of 10-32. We also changed the keywords so that they do not duplicate the words in the title of the manuscript. Keywords are now on lines 24-25 (instead of 33-34)

Line 188-190: I suggest a more detailed description of the controlled conditions for plant growth.

Response: That was done. Description of growing conditions added on lines 157-170. The line numbering has changed as the abstract and introduction have been shortened:

Plants were grown in a thin layer of organo-mineral substrate on the original layered vegetation and irradiation equipment with an area of one layer of 3 m² (Figure 1) [41]. Illumination in the experiment was 20-25 klx, photoperiod - 12 h, temperature - 24±2℃ during the day and 18±2℃ at night. The light source was high-pressure sodium lamps DNaZ-400 (“Reflax” LLC, Moscow, Russia). Accessions of R. sativus were sown with dry seeds in a growing medium based on high-moor peat (manufacturer – LLC Pindstrup, Russia) with the addition of Cambrian clay and chalk [ 42], substrate pH 6.0–6.2. The thickness of the root layer was 3-4 cm, the sowing scheme for small radish was 10 x 5 cm, for daikon - 12 x 10 cm. Watering was carried out daily: with water, alternating with fertilizing (Knop’s solution with the addition of ammonium nitrate 0.2 g/liter) 3 times a week. Harvesting of small radish plants was carried out on the 21-30th day from sowing, daikon - on 25-45th day from sowing. Three replicates and five plants per replicate for each accession were used.  

In addition, we have added to the section Materials and Methods a description of the conditions for growing mother plants (lines 192-196):

To stimulate and accelerate the flowering and maturation of seeds, the following cultivation regime was used: the roots of mother plants were kept in a thermostat at 5 degrees for 15 days after harvesting. After that, they were grown in 2 liter containers with a 16-hour photoperiod. The plants were pollinated by hand. The growing medium, illumination, temperature, and irrigation scheme were used as described above.

Line 218: It is recommended to describe the indicators of each component and their measurement methods.

Response: That was done. Description of measured components added to lines 197-200:

When harvesting, the main biometric indicators of plants were measured– plant, root and leaves weight, rosette height and diameter, number of leaves, length and width of leaf and petiole, length and diameter of root, as a number of bolted plants and degree of pubescence of leaves [45]. 

Line 448-451: “Another source of the ‘root diameter’ trait, cultivar ‘Octava’, was also characterized by 100% resistance to bolting and low pubescent leaves, which, however, were larger in size in comparison with cultivar ‘Viola’ (Table 3).” Here it is show that the ‘root diameter’ of ‘Octava’ is larger compared to ‘Viola’ and ‘Octava’, and it is recommended to add specific measured values for comparison when describing. The same is true elsewhere in the text.

Response: That was done. Specific measured values were added to lines 477-497:

The parent small radish cv. ‘Viola’, the source of the “root diameter” trait (mean is 3,29 cm), is characterized by a whole range of breeding valuable traits. So, in addition to 100% resistance to bolting, it has a compact leaf rosette and glabrous leaves. Another source of the “root diameter” trait, cv. ‘Octava’(mean is 3.17 cm), was also characterized by 100% resistance to bolting and glabrous leaves. However, leaf rosette of cv. ‘Octava’ was larger in size in comparison with cv. ‘Viola’ (Table 3): rosette height and diameter were larger at 11.9% and 18.3%, respectively; number of leaves was 14.2% higher than that for cv. ‘Viola’; leaf length and width were larger at 24.7% and 41.9%, respectively. Differences between the height and diameter of the rosette, as well as the length and width of the leaves were significant (p < 0.05). Small radish cv. ‘Pernot’, the source of the trait "length of the root"(mean is 8.29 cm), was characterized by a compact leaf rosette and medium pubescent leaves. Another source of the trait "length of the root", the daikon ‘Peterburgskiy’ (mean is 11.15 cm), is generally adapted to light culture. Its breeding was carried out for the open ground conditions of the Northwestern region of Russia, but with partial use of controlled conditions [44]. Along with the early start of root growth (the average weight of roots is about 50 g on the 40-45th day of vegetation), it has a leaf rosette that is quite compact for daikon, and a low pubescent leaves. It should be noted that the daikon has a larger rosette with more leaves compared to the small radish (Table 3). The maximum differences were observed by traits "diameter of the rosette" and "number of leaves", the excess over the small radish cultivars were 46.5-73.4% and 69.3-93.3%, respectively, differences are significant (p < 0.05). 

and 521-523:

Heterosis was observed in small radish F₁ hybrids not only by root weight, but also by leaf size and weight (Table 2). The weight of the plants, roots and leaves of the hybrids was 160.1%, 155.1% and 171.4% higher compared to the best parent cultivar, respectively. 

 

Conclusions: The conclusion of the article is too lengthy, and it is recommended to reduce it to about 150 words.

 

Response: That was done. Conclusion was reduced almost twice: from 342 to 199 words. If necessary, we will try to reduce it even more.

 

We sincerely thank you for your evaluation of our work and your comments.

 

Authors

 

Author Response File: Author Response.docx

Reviewer 2 Report

The  manuscript entitled "Breeding approaches for controlled conditions of artificial light culture for small radish and radish" is well written. The authors have provided good quality picture. The results are clear and convincing. Methodology have described well. The outcome of this study is beneficially to the vegetable breeders. 

However, the following issues need to be adressed in order to improve the quality of manuscipt.

1. The keywords are repeated with the words of title  of manuscript.I think , authors need to provide suitable words, which should reflect the  theme of whole study

2. "The purpose of presented work was to create of new accessions of small radish and 142 radish with a complex of economically valuable traits, intended for cultivation under con- 143 trolled environmental conditions, on the basis of the original author's methodology accel- 144 erated transgressive breeding" Please Provide  or replace this paragraph with the clear and logical statement.

3. The authors mentions the full details about phenolic compounds, color , dietary importance and other aspects in introduction section. I think it will be better add one  paragraph about the economic importance of radish.

4.  I also suggest, authors need to improve  and rearrange the introduction, which should be related to current study.

5. The authors have mentioned in table 1 about the flower induction and novel colour. what actually authors conducted experiments  for this study.

6. About flavonoids , please read the following manuscript

https://doi.org/10.3390/ijms22179544

7. I have found some typing and gramer mistakes. Please check throughout the manuscript.

8. I have found some meaningless sentences. Please check and rewrite.

9. Conclusion is too big. The authors need to provide brief and logically conclusion rather than abstract. 

I have found some typing and gramer mistakes. Please check throughout the manuscript.

 I have found some meaningless sentences. Please check and rewrite.

Author Response

Dear Reviewer,

We have tried to make changes according to your recommendations.

1. The keywords are repeated with the words of title  of manuscript.I think , authors need to provide suitable words, which should reflect the  theme of whole study

Response: We tried to provide suitable words for the keywords (lines 24-25):

 Keywords: Raphanus sativus L., selection and genetic research, CEAL, transgression, economically valuable traits, yield

2. "The purpose of presented work was to create of new accessions of small radish and 142 radish with a complex of economically valuable traits, intended for cultivation under con- 143 trolled environmental conditions, on the basis of the original author's methodology accel- 144 erated transgressive breeding" Please Provide  or replace this paragraph with the clear and logical statement.

Response: We have reformulated the purpose of the work (lines 111-116):

The aim of presented work was to evaluate the collection of accessions of R. sativus under artificial light conditions according to physiological and morphological traits, to search for sources of economically valuable traits, and to breed on their basis new highly productive forms of small radish and radish intended for cultivation in CEAL. For this purpose the original author's accelerated breeding methodology was used, described below.

3. The authors mentions the full details about phenolic compounds, color , dietary importance and other aspects in introduction section. I think it will be better add one  paragraph about the economic importance of radish.

Response: We generally shortened and changed the introduction according to paragraph 4 of the reviewer's comments. Also, we have shortened the introductory part on the biochemical components of radishes (lines 83-93). In addition, we have added information about the nutritional use of radishes (lines 80-83):

Radish and small radish (Raphanus sativus L.) belong to the extremely diverse and numerous Brassicaceae family, different forms of which are used in the food and pharmaceutical industries. Crops of the R. sativus are grown on large areas in Asia, Europe, America and Australia, mainly in open ground. Small radish, a mutant dwarf form of radish, is also commercially grown in greenhouses [19, 24, 25]. Radish and small radish are important components of a balanced healthy diet of the human population. Radish is consumed almost all over the world because of its fleshy edible roots that are used as a fresh salad, as well as salted, pickled, canned and dried, and added to soups and sauces or stewed. In addition, the young leaves are cooked and used as leafy greens [29]. Roots of the R. sativus have a high antioxidant potential and contain a significant amount of biologically active compounds: vitamins, polyphenols, terpenoids, glucosinolates (GLSs) and breakdown products GLSs, as well as mineral elements (potassium, calcium, etc.) [19, 29, 31]. Usually, their content in leaves significantly exceeds that in roots [31, 32]. It has been shown that young leaves of small radish and radish are rich in protein, amino acids, fiber, fatty acids, ascorbic acid, calcium, magnesium, and potassium. Leaves also contain a large number of compounds with antioxidant properties: polyphenols such as phenolic acids, flavonoids (isoflavones, flavonones, anthocyanins); as well as glucosinolates and phytosterols [31, 33-35]. It is well known that such compounds have hepatoprotective, antitumor and hypoglycemic properties [34, 36-38]. It was demonstrated that the antioxidant activity of red radish leaves was 3 times higher than that of roots [35]. Due to their valuable biochemical composition, young radish leaves can serve as components of a healthy diet in fresh salads and other culinary products, as well as raw materials for the production of nutraceuticals [29, 31, 34, 39].

4.  I also suggest, authors need to improve  and rearrange the introduction, which should be related to current study.

Response: We hope that we managed to make the introduction more relevant to the topic of this work. Now it has become shorter and, in our opinion, better corresponds to the goals of the tasks of the article (lines 28-116):

The relevance of the research is associated with the growing role of artificial climate facilities in crop production and the need of the best adaptation of grown crops to new technologies. The demand of improvement of existing and integrate new technologies in agriculture is conditioned by the development of human society, including population growth and large-scale urbanization, as well as global climate change, which has affected all regions of the world in recent decades. The threat of climate risks associated with crop loss is increasing everywhere [1-3], and, according to analysts, can lead to a significant reduction of crop quantity and quality. Due to this, technologies associated with crop production in fully controlled conditions, isolated from the influence of the external environment, are among the most dynamically developing [4, 5]

Currently, automated plant factories of various types are used for the plant cultivation and crop production in many countries. At the same time, production under the controlled environment with artificial light (CEAL, light culture) is constantly developing and improving, both in the field of technology and the range of cultivated crops [6–9]. However, significant capital and operating costs are still the main obstacle to the speed spread and development of plant factories. The production of different crops in CEAL requires the modern high-tech and expensive equipment for control and monitoring, as well as significant costs of electricity for illumination and air conditioning [7, 10]. This is one of the reasons why the range of crops grown in CEAL is still quite limited: it is determined primarily by economic efficiency. These are predominantly fast-growing green leafy vegetables, herbs, microgreens, and some fruiting crops [11–14]. The development and improvement of CEAL technologies requires to expand the range of crops and to increase their adaptation to the controlled environmental conditions. This can be achieved through suitable selection and breeding of relevant varieties to perform in the artificial light culture [12, 15, 16].

Traditionally the breeding of available on the seed market cultivars and hybrids was carried out for open or protected ground, under conditions that are very different from those in CEAL. So, in the open field, plants need resistance to the action of various abiotic and biotic stressors, and it is one of the target traits in breeding programs; however, controlled conditions require other traits and properties for selection and breeding. This is probably the reason for the decrease in potential yield and quality among many of these cultivars in plant factories [15–17]. Breeding and genetic studies are particularly relevant today, that aimed at creating new forms of agricultural crops for CEAL, taking into account its characteristics and the needs of producers [15, 16]. For this purpose, phenotyping of collections, qualitative and quantitative assessment of the accessions and identification of breeding-valuable traits sources are currently being carried out in light culture [18–21].

Currently, under controlled conditions, using specially selected growing regimes that accelerate the generative development of plants, genetic breeding studies of various crops (Cereals, Oilseeds, Legumes, Vegetable and Fruit Crops) are being carried out. CAEL allows researchers to conduct a number of key breeding stages regardless of the season, while significantly reducing the amount of breeding material being worked. Besides, time of creating new lines and cultivars is reduced by two or more times [22-26]. Under controlled conditions of light culture, it is possible to most accurately identify the key QTL responsible for the manifestation of economically valuable traits as well as the change in their localization in the genome under changing growing conditions [20, 27, 28]. Thus, the use of CEAL in the breeding process now serves as a powerful tool for its speeding up and increasing efficiency.

Radish and small radish (Raphanus sativus L.) belong to the extremely diverse and numerous Brassicaceae family, different forms of which are used in the food and pharmaceutical industries. Crops of the R. sativus are grown on large areas in Asia, Europe, America and Australia, mainly in open ground. Small radish, a mutant dwarf form of radish, is also commercially grown in greenhouses [19, 24, 25]. Radish and small radish are important components of a balanced healthy diet of the human population. Radish is consumed almost all over the world because of its fleshy edible roots that are used as a fresh salad, as well as salted, pickled, canned and dried, and added to soups and sauces or stewed. In addition, the young leaves are cooked and used as leafy greens [29]. Roots of the R. sativus have a high antioxidant potential and contain a significant amount of biologically active compounds: vitamins, polyphenols, terpenoids, glucosinolates (GLSs) and breakdown products GLSs, as well as mineral elements (potassium, calcium, etc.) [19, 29, 31]. Usually, their content in leaves significantly exceeds that in roots [31, 32]. It has been shown that young leaves of small radish and radish are rich in protein, amino acids, fiber, fatty acids, ascorbic acid, calcium, magnesium, and potassium. Leaves also contain a large number of compounds with antioxidant properties: polyphenols such as phenolic acids, flavonoids (isoflavones, flavonones, anthocyanins); as well as glucosinolates and phytosterols [31, 33-35]. It is well known that such compounds have hepatoprotective, antitumor and hypoglycemic properties [34, 36-38]. It was demonstrated that the antioxidant activity of red radish leaves was 3 times higher than that of roots [35]. Due to their valuable biochemical composition, young radish leaves can serve as components of a healthy diet in fresh salads and other culinary products, as well as raw materials for the production of nutraceuticals [29, 31, 34, 39].

The morphological characteristics of the radish vary greatly between different accessions. R. sativus is extremely diverse in term of root shape, weight and color, as a size and characteristics of leaf rosette [29]. It is used in research programs for genetic improvement and adaptation of new accessions to the formed environmental conditions [29, 40]. Small radish and compact, early ripening forms of radish are of great interest for production under light culture conditions. They have all the necessary characteristics that are required for crops grown in CEAL on multi-tiered growing systems: a short crop season, a compact habit and high nutritional properties. These reasons led to the choice of R. sativus as the object of our investigations aimed at creating new forms of plants in order to expand the range of crops cultivated in CEAL. One of the possible directions of radish breeding is the creation of productive forms with a glabrous leaf, which makes it possible to use plants as food as a whole. It can significantly increase the productivity and profitability of cultivating of the crop, especially in controlled conditions.

The aim of presented work was to evaluate the collection of accessions of R. sativus under artificial light conditions according to physiological and morphological traits, to search for sources of economically valuable traits, and to breed on their basis new highly productive forms of small radish and radish intended for cultivation in CEAL. For this purpose the original author's accelerated breeding methodology was used, described below.

5. The authors have mentioned in table 1 about the flower induction and novel colour. what actually authors conducted experiments  for this study.

Response: We have removed the Table 1 in the latest version of the manuscript. Table 1 was cited from Folta, K.M. Breeding new varieties for controlled environments. Plant Biol. 2019, 21, 6-12. We have replaced it with a description in the text. In our work, we used the growing regime for the mother plants, which accelerates their transition to bolting and flowering. It is described in the Materials and Methods section on lines 192-196:

To stimulate and accelerate the flowering and maturation of seeds, the following cultivation regime was used: the roots of mother plants were kept in a thermostat at 5 degrees for 15 days after harvesting. After that, they were grown in 2 liter containers with a 16-hour photoperiod. The plants were pollinated by hand. The growing medium, illumination, temperature, and irrigation scheme were used as described above.

6. About flavonoids , please read the following manuscript https://doi.org/10.3390/ijms22179544

Response: We are very grateful for your clarification. We have corrected the sentence about flavonoids. Now it's like this (lines 89-92):

Leaves also contain a large number of compounds with antioxidant properties: polyphenols such as phenolic acids, flavonoids (isoflavones, flavonones, anthocyanins); as well as glucosinolates and phytosterols [31, 33-35]. 

7. I have found some typing and gramer mistakes. Please check throughout the manuscript. We have tried to correct the errors found in the text.

Response: We have tried to correct all the mistakes we found in the text. We will be very grateful to you if you highlight in the new version of the manuscript the places that need to be corrected (if they remain), in yellow, red or any other color. Then we will understand what we should pay special attention to.

8. I have found some meaningless sentences. Please check and rewrite.

Response: We have tried to correct all the meaningless sentences we found in the text. If you don't mind, please highlight such places in the text of the manuscript, if they remain after the correction. We will be very grateful to you.

9. Conclusion is too big. The authors need to provide brief and logically conclusion rather than abstract. 

Response: We have shortened the Conclusion and tried to make it better and clearer (lines 636-649): 

The genetic diversity and breeding potential of cultural forms of R. sativus with different lengths of the growing period (small radish, daikon) were studied under controlled conditions with artificial light. Accessions were identified - sources of valuable traits for CEAL. New accessions of R. sativus with a complex of economically valuable traits were created that are transgressive in term of root weight. The yield of the roots of new small radish forms was 4.30 - 4.98 kg/m² for 25 days of cultivation under light culture conditions. Radish lines from crossing of small radish and daikon had a longer growing period – 40 - 45 days, and their yield was 5.46 - 7.66 kg / m² per growing season under light culture conditions. All created accessions of R. sativus are characterized by a complex of economically valuable traits: a compact leaf rosette, glabrous leaves, high values of the index of economic efficiency and the index of attraction, resistance to premature bolting.

All selection and genetic studies were conducted under CEAL conditions. It has significantly reduced the amount of material involved in the research, as well as the time spent on the creating of new forms R. sativus (up to 4-5 years).

Author Response File: Author Response.docx

Reviewer 3 Report

The article "Breeding approaches for controlled conditions of artificial light 2 culture for small radish and radish (Raphanus sativus L.)" is a well-executed study and well-written as well. The article will enlighten the new breeding approaches for radish.

There are some linguistic mistakes that need to be addressed.

The introduction is well formulated but the objective of the study is not up to the mark. I recommend to re-write the objective in more detail.

The discussion needs to be more connected with studied attributes and also conducted the PCA analysis for the varieties to understand more about cultivars and their studied attributes.

Minor changes required

Author Response

Dear Reviewer,

We are very grateful to you for your evaluation of our work. We tried to take into account all your comments and respond to them:

1. There are some linguistic mistakes that need to be addressed.

Response: We have tried to correct all the mistakes we found in the text. However, we will be very grateful to you if you highlight in the new version of the manuscript the places that need to be corrected (if they remain), in yellow, red or any other color. Then we will understand what we should pay special attention to.

2. The introduction is well formulated but the objective of the study is not up to the mark. I recommend to re-write the objective in more detail.

Response: We hope that we managed to make the introduction more relevant to the topic of this work. Now it has become shorter and, in our opinion, better corresponds to the goals of the article. We also re-writed the objective of the work (lines 111-116):

The aim of presented work was to evaluate the collection of accessions of R. sativus under artificial light conditions according to physiological and morphological traits, to search for sources of economically valuable traits, and to breed on their basis new highly productive forms of small radish and radish intended for cultivation in CEAL. For this purpose, the original author's accelerated breeding methodology was used, described below.

3. The discussion needs to be more connected with studied attributes and also conducted the PCA analysis for the varieties to understand more about cultivars and their studied attributes.

Response: We conducted a PCA analysis for the varieties and supplemented the article with its results: 

Lines 216-220 in Statistical Analysis

The variability of the structure of feature relationships was evaluated using principal component analysis (PCA). Factor loads were expressed in correlation coefficients with the factor. In addition, the eigenvalues for each factor, the share of factors in the total variance, and the cumulative share of extracted factors were calculated. The selection of the number of optimal factors was carried out using the Scree test [46].

And lines 244-289 in Results, including Table 1 and Figure 2:

3.1 Principal Component Analysis (PCA)

In breeding, the correlated inheritance of quantitative and qualitative traits of leaves, rosettes and roots is interesting.

Based on the evaluation results, 112 accessions of small radish were grouped by type. As a result of the analysis of 12 phenotypical traits according to the method of principal component analysis (PCA), it was found that their variability is determined by six factors. Together, they determine 92,1% of the total variance. At the same time, the first component that characterizes the parameters of the rosette and the leaf (the height and diameter of the rosette, the length and width of the leaf) and the weight of the plant determines 45.9% (Table 1).

Table 1. Factor structure of variability of features of 112 accessions of small radish

Variable	Factor Loadings (Varimax raw) Extraction: Principal component
	PC1	PC2	PC3	PC4	PC5	PC6
Rosette Height Rosette Diameter Leaf Length Leaf Width Root Length Root Diameter Root Index Plant Weight Root Weight Duration of Vegetative Phase Number of bolted plants Degree of pubescence Expl.Var Prp.Totl % total variance % cumulative proportion of variance	0,89 0,74 0,89 0,91 0,23 -0,02 0,21 0,72 0,29 0,29 0,15 -0,13 3,75 0,31 45,9   45,9	0,25 0,15 0,09 0,12 0,86 -0,88 0,94 0,14 0,06 0,18 -0,14 -0,12 2,60 0,22 19,1   65,1	0,05 0,17 0,07 0,05 0,08 -0,07 0,07 0,15 0,10 0,17 -0,15 -0,95 1,05 0,09 9,8   74,8	0,08 0,20 0,13 0,17 0,37 0,39 0,14 0,50 0,91 0,16 0,09 -0,09 1,53 0,13 7,7   82,5	0,15 0,09 0,26 0,05 0,15 0,01 0,14 0,25 0,14 0,91 -0,03 -0,15 1,07 0,09 4,6   87,4	0,06 0,25 0,10 0,00 -0,04 0,13 -0,05 0,13 0,10 -0,04 0,95 0,15 1,05 0,09 4,8   92,1

The second component determines the length, diameter and index of the root. The third determines the degree of pubescence, the fourth determines the root weight, the fifth determines the duration of the vegetative phase and sixth determines number of bolted plants.

Thus, the analysis demonstrates the relationship between the characteristics of the leaf and the rosette with the signs of weight plant. The length root and root index are negatively related to the root diameter (Table 1).

Since the first two components characterize the largest part of the variability of features, we considered the location of accessions in their space. As a result, the accessions were divided into four groups (Figure 2). The first group includes 11 accessions type While Icicle and French Breakfast, which are characterized by a large rosette of leaves, a long root and an average duration of vegetative phase. These are mainly accessions from Europe, Russia, Canada, Chile and Turkey.

The second group includes 11 accessions of French Breakfast type and 1 accession of Scarlet globe type. The accessions are characterized by a cylindrical shape of the root, small size of the rosette of leaves and medium pubescence of the leaves.

Figure 2. Distribution of accessions small radish in the space of the first two components. The color indicates the types of accessions.

The accessions of the third group were characterized by a large variability in the combination of the studied features and formed a rather large and sparse cloud in the factor space. This group includes accessions of Saxa type (47 acc.), Burpee’s white (4 acc.), Pink-red with a White Tip (12 acc.), Scarlet globe (3 acc.), Würzburg (2 acc.), Yellow (2 acc.), French Breakfast (1 acc.), Hailstone (1 acc.), Pinkie (1 acc.), Purple (1 acc.) and Red Giant (1 acc.).

Generally, of particular interest are samples of groups 4, 5, 6 and 7 with extreme values of individual traits that exceed the established limits of these traits for the types to which they belong. However it should be noted that the identified cultivar ‘Viola‘- sources of selected traits "root diameter" was into the 3th group, and cv. ‘Pernot‘ - the source of the trait "root length" – was into the 2th group. Cv. ‘Octava‘ - sources of the trait "root diameter" - belonged to the 7th group. We took into account the presence of a complex of economically valuable traits when selecting accessions for subsequent crossing, which will be discussed below. Based on this, the most promising parent varieties belonged to the groups 2, 3 and 7.

After that, we added some specific measured values (and discussion) to lines 477-497:

The parent small radish cv. ‘Viola’, the source of the “root diameter” trait (mean is 3,29 cm), is characterized by a whole range of breeding valuable traits. So, in addition to 100% resistance to bolting, it has a compact leaf rosette and glabrous leaves. Another source of the “root diameter” trait, cv. ‘Octava’(mean is 3.17 cm), was also characterized by 100% resistance to bolting and glabrous leaves. However, leaf rosette of cv. ‘Octava’ was larger in size in comparison with cv. ‘Viola’ (Table 3): rosette height and diameter were larger at 11.9% and 18.3%, respectively; number of leaves was 14.2% higher than that for cv. ‘Viola’; leaf length and width were larger at 24.7% and 41.9%, respectively. Differences between the height and diameter of the rosette, as well as the length and width of the leaves were significant (p < 0.05). Small radish cv. ‘Pernot’, the source of the trait "length of the root"(mean is 8.29 cm), was characterized by a compact leaf rosette and medium pubescent leaves. Another source of the trait "length of the root", the daikon ‘Peterburgskiy’ (mean is 11.15 cm), is generally adapted to light culture. Its breeding was carried out for the open ground conditions of the Northwestern region of Russia, but with partial use of controlled conditions [44]. Along with the early start of root growth (the average weight of roots is about 50 g on the 40-45th day of vegetation), it has a leaf rosette that is quite compact for daikon, and a low pubescent leaves. It should be noted that the daikon has a larger rosette with more leaves compared to the small radish (Table 3). The maximum differences were observed by traits "diameter of the rosette" and "number of leaves", the excess over the small radish cultivars were 46.5-73.4% and 69.3-93.3%, respectively, differences are significant (p < 0.05). 

and 521-523:

Heterosis was observed in small radish F₁ hybrids not only by root weight, but also by leaf size and weight (Table 2). The weight of the plants, roots and leaves of the hybrids was 160.1%, 155.1% and 171.4% higher compared to the best parent cultivar, respectively. 

We sincerely hope that the manuscript has become better and more informative after the changes and additions made.

 

Kind regards,

Authors

Author Response File: Author Response.docx