Genetic Variability in a Population of Oilseed Rape DH Lines Developed from F1 Hybrids of a Cross between Black- and Yellow-Seeded DH Lines. II. Seed Quality
Round 1
Reviewer 1 Report
There were some sections in the manuscript that would benefit from revision as detailed below.
How robust is the correlation analysis? Can the authors consider a correlation of -0.34 robust enough although significantly different to affirm that there is a negative correlation between seed colour and fat content? (line 183)
All the tables are missing some bold letters in the significant at alfa =0.01 level
Figure 2: For clarity, I recommend to add the x and y axis labels in the figures. Also, specify that the frequency of distribution is for DH lines specifically (and not the parental lines)
Figure 3: For clarity, add the y axis label in the figure.
Section 3.4: For clarity for the reader, the authors can link the results of Table 5 with Figure 3.
Except in the case of protein, when it is mentioned that it is influenced by the environment interaction with the genotype, do the authors consider that the differences that they are seeing can be affected by the environment? This was not discussed in the discussion section of the manuscript? Were the other studies that the authors are referring to (40, 43, 49, 50) in line 311, performed in the field or controlled conditions?
Do the authors consider DH-16 and DH-30 lines to be of use for breeders? Do you expect that the results observed for these 2 lines to hold in different environment conditions?
Material and methods: Plant material section: How the DH H2-26 plants were obtained? There is a detailed explanation about how DH Z-114 seeds were obtained but not for DH H2-26.
Experimental conditions: Lines 94-95. Can the authors include in the manuscript what is the reason that fat content was taken from open-pollinated plants meanwhile GSL, protein, NDF and ADF were measured from self-pollinated plants?
Methods of statistical analysis: The experiment was carried out in a randomised block design. In line 106 the authors specify a two-factor analysis of variance, where genotypes and environments were taken into account. Did the authors take into account the effect of the block design? This is very relevant and was not sufficiently described.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript has a very simple objective, to characterize the variability in the chemical composition of seeds in a Winter oilseed rape DH population. Evaluation in field trials for two years is valuable. Nevertheless, my main concern is the very small size of the population (only 44 lines). Such a small population limits the estimates of variance components. It also limits its usefulness for deeper genetic and molecular studies. In addition, meteorological data, fertilization level, and seed productivity level for each experimental year need to be incorporated and disscused properly (see below). Given that there are other larger mapping populations in the world, the relevance of the information and contribution to knowledge in this manuscript is limited.
Detailed comments:
2.1. Experimental conditions: Include a brief summary on meteorological conditions for both experimental years, along with basic data on crop phenology (date of emergence, start of flowering, maturity). Did the DH lines have a similar time to flowering? Was the length of the post-flowering period (when grain filling occurs) similar between lines and years?
Figure 2: Panel (B) Protein content tended to be lower in year I. Is this related to a higher level of seed yield in year I? Panel (F) Seed from year I tendend to be darker than year II. It is surprising to me, since the morphological traits (size, shape, color) are usually quite conservative. To what causes (environmental)) can you attribute it? Point this result out to the readers on Results section, and then discuss it in the Discussion section.
Figure 3: Are the data the average of both years? There was no significant effect of year? Explain.
Further discussion of the results of this manuscript is necessary, connected with the seed yield results already published (Szala et al 2021 Euphytica). ‘In the DH population studied here, three low-fibre DH lines were found, which tended to have a significantly increased protein content, with no corresponding effect on fat content’ (see lines 257-261). What was the level of seed yield on these lines? Is there any association between seed yield and fiber content in the DH population? Although a comment is made (in lines 324-326), I suggest expanding the discussion between productivity and seed composition to all the DH lines studied.
‘The protein content in seeds was strongly influenced by the environment and genotype-environment interaction, but a genetic factor also had a significant influence’ (…) ‘indicating that selection for a lighter colour could lead to a higher protein content in seeds.’ (see lines 272-282). It is known that the seed protein content is strongly explained by the availability of N (mostly accumulated in the biomass) and the number of seeds set at flowering. Thus, the seed protein tends to decrease under high yield conditions (N dilution effect in a greater number of seeds). In contrast, protein tends to increase under low-yield conditions. Thus, it would be very useful to include a scatter plot of protein content versus seed yield, identifying the most promising lines (with high yield, high protein, and low fiber).
‘GSL content turned out to be the most variable of the biochemical traits. (…) and there were significant differences in the content of these compounds in both years of the study.’ To what causes can you attribute it? Were there contrasting environmental conditions between years (temperature, rainfall)? As GLS contnet can respond to S fertilization, I suggest discussing the level of fertilization with S, and the level of seed yield (dilution of S in a different number of grains).
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Authors have revised the manuscript, improving it mostly. I consider it sufficient to be published.
