Abstract
High yields of seeds, green pods and green biomass is the main goal of soybean breeding in many countries. An assessment of relationships between the productivity traits and their effect on the yield may be useful in developing effective crop cultivation programs. In soybean, the stem growth habit and the branching character are interrelated with plant productivity and in most cases determine it. Therefore, the aim of the present work was to study the variability of the level (strength) and the structure of correlations between 92 morphological, phenological, biochemical, agronomic traits of soybean accessions with different growth habits, and branching characters in different weather conditions. 270 soybean accessions of different ecological and geographical origin from the VIR collection have been grown in the Krasnodar region within 3 years. Field studies of the traits and biochemical analysis were carried out according to VIR guidelines. The variability of correlation matrices as regards the strength and structure of relationships was analyzed using the correlation and factor analysis (the principal component method), as well as the method developed by N.S. Rostova. A comparison of the level (R2, coefficient of determination) and structure of correlations in different years has shown that the deterioration of external conditions is followed by an increase in the strength of relationships (R2) between the traits and in the difference between correlation matrices’ structure. Soybean adaptation to the changing conditions occurs due to the rearrangements of relationship systems, whereas the degree and direction of these changes are determined by the growing conditions and specificity of the accessions response. Under favorable conditions, the structure of correlations in soybeans with different growth habits, and branching characters has more similarity than in the conditions critical for development. The highest level of relationships (R2) between the traits was observed in the year that was unfavorable for the growth of the semi-cultivated accessions (with the indeterminate growth habit and a large number of branches of the 1st and 2nd order). The green biomass productivity of accessions with the determinate growth habit and more than two branches is most strongly associated with the branch weight, while in accessions with the indeterminate growth habit and with (or without) 1–2 branches it depends on the growing season duration, one leaf weight and the number of leaves per plant. In the semi-cultivated accessions (with the indeterminate growth habit and numerous branches of the 1st and 2nd order), it correlates, besides the listed traits, with the number of nodes, the internode length, the main stem diameter, the weight of leaves, seed morphometric parameters and their quality.
Highlights
Soybean is one of the most economically important leguminous crops, ranking first among them in the world in terms of cultivated areas
Previous studies have shown that the type of stem growth in soybean is mainly controlled by the Dt1 locus; the indeterminate growth habit is dominant or not fully dominant with respect to the determinate dt1 (Woodworth, 1932)
The studied traits got distributed into the factors of growth habit, seed weight and size, growing season duration, plant height, seed biochemical composition, leaf size and shape, green biomass biochemical composition, plant color, the content of anti-nutrients in seeds, inflorescence parameters, and of green biomass yield
Summary
Soybean is one of the most economically important leguminous crops, ranking first among them in the world in terms of cultivated areas (http://www.fao.org/faostat). Soybeans are characterized by several types of the main stem growth: the varieties with indeterminate and determinate growth habit are distinguished. Previous studies have shown that the type of stem growth in soybean is mainly controlled by the Dt1 locus; the indeterminate growth habit is dominant or not fully dominant with respect to the determinate dt (Woodworth, 1932). The phenotype is determinate in the dt1/dt genetic backgrounds, because dt is epistatic to Dt2 and dt (Bernard, 1972) It has been reported about the identification of the third allele in the Dt1 (dt1-t) locus, which produces a phenotype with some characteristics of both dt and Dt2 (Thompson et al, 1997). The transition from the indeterminate to determinant type occurred through four independent single-nucleotide substitutions, each of which resulted in the replacement of amino acids (Tian et al, 2010)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call