Genetic Analysis of Certain Quantitative Traits in Forage Sorghum (Sorghum Bicolor L. Moench)

Abstract

Genetic analysis of certain quantitative traits in forage sorghum (Sorghum bicolor L. Moench).” The present investigation entitled “Genetic analysis of certain quantitative traits in forage sorghum (Sorghum bicolor L. Moench).” was undertaken to collect information on genetic parameters for yield and its components from a ten parents diallel mating design in forage sorghum at Crop Research Centre, Sardar Vallabhbhai Patel University of Agriculture & Technology, Meerut (U.P.) during kharif 2021 and 2022. The experimental material was comprised of 10 diverse parents and their 45 F1s excluding reciprocals of a diallel cross. All genotypes were evaluated in a complete randomized block design with three replications. The data were recorded on ten characters i.e., days to 50% flowering, plant height, leaf length, leaf breadth, stem girth, leaves per plant, leaf area, leaf stem ratio, total soluble solids and green fodder yield. The data were recorded subjected to various statistical analyses. Analysis of variance for parents and crosses recorded highly differed significantly for all the attributes namely, days to 50% flowering, plant height, leaf length, leaf breadth, stem girth, leaves per plant, leaf area, leaf stem ratio, total soluble solids and green fodder yield, while parent vs crosses had highly significant for all the characters, indicated that presence of wide differences among the parents and F1’s hybrids. High heritability accompanied with high genetic advance as percent of mean was noted for leaf breadth, stem girth, leaves per plant, leaf area, leaf stem ratio, total soluble solids and green fodder yield per plant, indicating that these attributes were highly heritable and selection of high performing genotypes is possible to improve these characters. Green fodder yield exhibited significant stable and positive correlation with plant height, leaf length, leaf breadth, stem girth, leaves per plant and leaf area at genotypic and phenotypic level. These characters may be considered as important yield component in forage sorghum. Leaf breadth displayed high order of direct effect on green fodder yield per plant followed by stem girth, leaf area, leaf stem ratio and leaves per plant at phenotypic and genotypic level, which indicates that the contribution of individual attributes to fodder yield is of importance in planning a sound breeding programme for developing for high yielding varieties. Estimates of additive genetic variance D was recorded positive significant for all the characters except leaf stem ratio which indicating predominance of additive gene action in the inheritance of these traits. Dominance components H1 and H2 recorded highly significant and positive for all the characters except leaf stem ratio in F1 generation. The estimates of H1 values were higher than the values of H2 for all the attributes, indicated that unequal allelic frequencies at relevant loci in the population. Measure of dominance effect h2 reported highly significant and positive for all the characters except leaf stem ratio and total soluble solids, which indicated that presence of dominance in F1 generation. Value of F was observed highly significant and positive for days to 50% flowering, plant height, leaf length, stem girth, leaves per plant, leaf area and total soluble solids in F1 generation, indicating the excess of dominant and positive allele in the parents for governing these attributes. Estimates for degree of dominance (H1/D)½ exhibited to be more than unity in F1 generation for all the ten characters viz., days to 50% flowering, plant height, leaf length, leaf breadth, stem girth, leaves per plant, leaf area, leaf stem ratio, total soluble solids and green fodder yield, suggested that the existence of over dominance for these attributes. Ratio of gene with positive and negative effects in the parents H2/4H1 was found less than unity theoretical value (0.25) for all the traits i.e., days to 50% flowering, leaf length, leaf breadth, stem girth, leaf area, leaf stem ratio, total soluble solids and green fodder yield in the F1 generation, which showed that dissimilar distribution positive and negative alleles. Proportion [(4DH1)½+F/(4DH1)½-F)] indicates the ratio of dominant and recessive alleles among the parents. It was recorded more than unity for all the attributes except green fodder yield, which indicated accumulation of dominant alleles in the parents for these traits. Ratio h2/H2 is an important measure of the group (s) of the genes controlling the attribute and exhibiting dominance. The value of this ratio was found more than unity for plant height, leaf breadth and green fodder yield ratio in F1 generation, indicated that more than one major gene groups are responsible for governing these characters and rest of the traits observed the proportion of h2/H2 less than one unity, indicating the presence of at least one major gene or gene group is controlling these attributes. The mean degree of dominance (σ2g/σ2s)1/2 was observed greater than unity for leaf stem ratio, indicating the involvement of over dominance for this trait, while it was less than unity for days to 50% flowering, plant height, leaf length, leaf breadth, stem girth, leaves per plant, leaf area, total soluble solids and green fodder yield, which indicated that the involvement of partial dominance for these characters. On the basis of overall per se performance and general combining ability effects among the lines, HC-136 for 7 characters, CSV-21 for 8 traits and CSV-17 for 9 attributes including green fodder yield were identified as good general combiners, which suggested that these parents may be used in the hybridization programme aimed devolvement of superior genotypes in forage sorghum. On the basis of overall findings and fodder yield performance the cross combinations i.e. CSV-21 x HC-136, HC-260 x G-48, GFS-5 x G-48, G-48 x Pant Chari-8 and CSV-17 x Pant Chari-8 were considered as best specific combiners for maximum traits including green fodder yield for 8 to 10 other contributing characters, which may be utilized for obtaining transgressive segregants in the next generation. On the basis of overall results and per se performance the manifestation of high degree of heterosis over better and mid parent in certain F1’s hybrids i.e., CSV-21 x HC-136, HC-260 x G-48, GFS-5 x G-48, UP Chari-3 x CSV-17 and CSV-17 x Pant Chari-8, identified that great possibility of developing hybrid for commercial cultivation.