Genetic Control for Percentage Grain Protein and Grain Yield in Grain Sorghum¹

Abstract

Inheritance of grain protein and yield was investigated in grain sorghum [Sorghum bicolor (L.) Moench]. Divergent selection was applied to a series of individual plants from the breeding nursery for high and low protein content. Protein percentage was determined from a random sample of finely ground grain by the Udy dye‐binding method. The selected lines were crossed onto A‐lines ‘Martin’ (high protein) and ‘Wheatland’ (low protein). Test crosses, parents, and checks were planted in replicated lattice‐designed tests at Clovis, N.M., for 3 years.Highly significant differences were detected between the lines selected for high and low protein content for both percentage of grain protein and grain yield. Significant differences also were found between the two female lines. Genetic analyses of the test crosses and their parents indicated that low protein content was partially conditioned by dominant genes. Of 155 test crosses, 3% produced grain protein content significantly below the lower parent, indicating negative heterosis; 35% of the test crosses were signifidcantly below their mid‐parent mean, indicating dominant genes for low protein. Grain yield was determined by dominant or overdominant gene action as 43% of the test crosses yielded significantly above their midparent mean, and 35% of the crosses yielded significantly more than the highest yielding parent. Protein percentage had a highly significant negative correlation with yield (r = ‐0.53, significant at the 0.01 level).Partitioning of the genetic variance indicated that additive gene action was more important than nonadditive gene action for both attributes studied. The genetic variances for males were greater than for females for both attributes; however, many more males were tested than females. Narrow‐sense heritability values of 35 and 44% were computed for grain protein percentage and yield, respectively.

Genotype by environment interaction using AMMI model and estimation of additive and epistasis gene effects for 1000-kernel weight in spring barley (Hordeum vulgare L.)

“…Epistasis effects involved in the models proved that genetic of these traits is complex and polygenic (Lander and Schork 1994 ; Lefebvre and Palloix 1996 ; Hermisson et al 2003 ; Crow 2010 ). Epistasis has been demonstrated for numerous features in a number of cultivars of following species: barley (Kularia and Sharma 2005 ; Bocianowski et al 2016 ), corn (Melchinger et al 1987 ; Li et al 2016 ), sugar beet (Abbasi et al 2015 ), rice (Matsubara et al 2015 ), oilseed rape (Bocianowski et al 2017 ), common wheat (Bnejdi and El Gazzah 2008 ; Jaiswal et al 2016 ), and sorghum (Finkner et al 1981 ).…”

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“…Estimates of quantitative-genetic parameters are necessary for computing the expected gain from direct or indirect selection, for optimizing selection strategies like the allocation of resources to number of replications, test environments and seasons, or for assessing the potential merit of a hybrid breeding program in a crop species. However, most quantitativegenetic studies with sorghum were conducted in the United States of America or in India, and do not refer to extreme and variable drought stress, or include only two or three environments (Kambal & Webster, 1965;Niehaus & Pickett, 1966;Beil & Atkins, 1967;Collins & Pickett, 1972;Jan-Orn et al, 1976;Singhania, 1980;Bittinger et al, 1981;Finkner et al, 1981;Mishra et al, 1992). Estimates obtained in those studies are therefore not directly applicable to the situation in semi-arid areas.…”

Ensaios preliminares sobre autofecundação e cruzamentos no melhoramento do capim-elefante

“…Expressões heteróticas e endogâmicas de caracteres quantitativos, como produção de MS, devem ser explicadas com base na natureza e na magnitude dos efeitos gênicos que as controlam (Finkner et al, 1981), o que não foi abordado neste trabalho.…”