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F 3 Yield Response to F 2 Selection for Gibberellic Acid Insensitivity in Eight Wheat Crosses 1
Author(s) -
O'Brien L.,
Pugsley A. T.
Publication year - 1981
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/cropsci1981.0011183x002100020002x
Subject(s) - seedling , biology , selection (genetic algorithm) , gibberellic acid , horticulture , randomized block design , yield (engineering) , grain yield , zoology , botany , agronomy , germination , materials science , artificial intelligence , computer science , metallurgy
The hypothesis that the Gai/Rht alleles have a positive pleiotropic effect on grain yield was investigated by examining the F 3 yield responses to F 2 seedling selection for GA 3 insensitivity within eight wheat( Triticum aestivum L.) crosses. Seedlings were liberally sprayed with a 100 ppm solution of GA 3 (Berelex) at the three‐leaf stage. Seven days after spraying they were visually sorted into two groups, those that were insensitive and those responsive to applied GA 3 as expressed by elongated internodes and a general etiolated appearance. Significant F 3 yield increases were obtained in response to F 2 seedling selection for GA 3 insensitivity in two out of four crosses with the Gai/Rht 1 genotype and three out of four crosses with the Gai/Rht 2 genotype. In seven out of the eight crosses, the highest yielding F 3 lines came from the GA 3 insensitive populations, but the large Least Significant Differences that resulted from the use of two replicate randomized complete block yield experiments meant the differences among lines were generally not significant. Selection for GA 3 insensitivity was simple and rapid, however, the visual classification into only two groups in this study meant that the so‐called GA 3 sensitive group contained plants heterozygous for GA 3 insensitivity. Actual measurement of the height to the second leaf node was the most reliable means of selection for GA 3 response among seedlings. Selection for reduced plant height at the F 2 seedling stage resulted in subsequent F 3 yield increase because of the positive pleiotropic effect of the Gai/Rht genotype on yield. The technique can be integrated with any breeding methodology.