Genetic Effects and Genetic Effect × Year Interactions at Three Gene Loci in Sublines of a Maize Inbred Line

Abstract

"Isogenic" lines of maize (Zea mays L.) inbred B14, differing by single marker genes and chromosome segments linked to these genes, were used to study gene action in the inheritance of 10 plant, ear, and grain characters. The 27 genotypes representing all combinations of the homozygous and heterozygous genotypes at three loci, rp, wx, and ws, were evaluated for three years. Highly significant differences among genotypes were observed for eight characters; genotype × year interactions were highly significant for seven characters, which included the two characters that were not different for genotypes. Additive effects were most important, followed by additive × additive epistasis, and dominance was relatively unimportant. Also, additive effects × years were generally the most important of the interactions, but except for the two characters that did not have significant differences among genotypes, the genotypic effect × year interactions were of considerably lesser importance than the genotypic effects.

Investigation on direct and reciprocal crosses in maize ( Zea mays L.)

“…This contradicted the findings of Russell (1976), who indicated no significant genotype × year interaction for plant height or ear attachment height. The genotype × year interaction for the length of the main tassel axis above the lowest side-branch was significant at 5%, while those for the length of the main tassel axis above the uppermost branch, for stalk diameter and for leaf number were not.…”

Quantitative Genetics of Heterosis

“…The standard Cockerham model was fit to the data to estimate additive, dominance, and epistatic effects. Russell (1976) found that 87, 27, 47,15,23, and 30% of the additive, dominance, additive x additive, additive x dominance, and dominance x dominance effects were significant at the 5% level, indicating that even at the population level, loci were interacting fairly frequently. This study also demonstrates the pleiotropic effect of loci.…”

“…Together, these two studies bring out the salient features of the analyses. Russell (1976) developed B 14 isolines of the 27 genotypes possible for three loci with two alleles. The experiment was grown for three years at one location and data were collected for 10 traits.…”

Sexto ciclo de seleção divergente para tamanho do pendão e altura de espiga na população de milho (<i>Zea mays</i> L.) ESALQ PB-1

“…Os estudos sobre os componentes da variação genética indicam que esses caracteres são controlados predominantemente por genes com efeitos aditivos (GARDNER et ai., 1953;STUBER et al, 1966;RUSSELL & EBERHART, 1970;HALLAUER, 1971;SUBANDI & COMPTON, 1974;RUSSELL, 1976;HALLAUER & MIRANDA FIRO, 1988); com relação ao grau médio de dominância, estimativas indicam a presença de dominância parcial relativa à maior altura de planta e de espiga, reforçando assim a hipótese de predominância de genes aditivos (COMSTOCK & ROBINSON, 1948;ROBINSON et al, 1949;GARDNER & LONNQUIST, 1959), demonstrando que esses caracteres podem ser reduzidos através do uso de seleção recorrente. ARAÚJO (1992), trabalhando com a população ESALQ PB-1, no quinto ciclo de seleção divergente para maior (E+) e menor (E-) altura de espiga, estimou a variância genética aditiva para altura de espigas na ordem de 167,35 e 68,85 (cm/planta) 2 , respectivamente.…”