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Simultaneous Evaluation of Grain Sorghum A‐Lines and Random‐Mating Populations with Topcrosses 1
Author(s) -
Hookstra G. H.,
Ross W. M.,
Mumm R. F.
Publication year - 1983
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1983.0011183x002300050039x
Subject(s) - biology , sorghum , germplasm , population , mating design , inbreeding , agronomy , grain yield , randomized block design , yield (engineering) , hybrid , horticulture , heterosis , demography , materials science , sociology , metallurgy
Grain sorghum [ Sorghum bicolor (L.) Moench] topcrosses from 19 A‐lines crossed to six random‐mating populations were evaluated for general combining ability (GCA) and specific combining ability (SCA) effects. Topcrosses were produced by interplanting short rows of the A‐lines within each population in an isolation block. Six replications of a split‐plot experimental design with populations as main plots and A‐lines as subplots were grown at Mead, Nebr., in 1979 and 1980. Data were recorded on seven traits. Significant differences were detected among A‐lines and among populations for grain yield, plant height, days to flowering, tillering, and percent oil and among A‐lines for 100‐seed weight and percent protein. No genotype ✕ year yield interaction was significant for either parental group. Significant A‐line ✕ population interactions existed for yield, height, and flowering although individual analyses by population often ranked the A‐lines similarly. There were no significant A‐line ✕ population ✕ year interactions. Based on GCA effects, A‐line N37 and population RP1R were superior parents for producing high yielding topcrosses. The SCA yield effects were significant in only eight topcrosses. N37 ✕ RP1R had the highest yield, but its SCA effect was nonsignificant. Topcrosses appear to be suitable for preliminary evaluation of grain sorghum germplasm. They identify superior A‐lines and identify populations in which to initiate inbreeding to develop R‐lines.