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Diallel Analysis of the Stay‐Green Trait and Its Components in Sorghum
Author(s) -
Oosterom E. J.,
Jayachandran R.,
Bidinger F. R.
Publication year - 1996
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/cropsci1996.0011183x003600030002x
Subject(s) - diallel cross , heterosis , biology , sorghum , overdominance , trait , senescence , dominance (genetics) , horticulture , quantitative trait locus , agronomy , botany , hybrid , genetics , gene , computer science , programming language
Stay‐green in sorghum [ Sorghum bicolor (L.) Moench] is an important component of post‐flowering drought tolerance. This research was conducted to describe (i) stay‐green as post‐flowering green leaf area duration (GLAD) and its components [green leaf area (GLA) flowering, timing for onset of senescence, and senescence rate] and (ii) the expression of heterosis for stay‐green in terms of heterosis for its components. The study was conducted during the 1992 to 1993 and 1993 to 1994 post‐rainy season at ICRISAT headquarters near Hyderabad, India. It involved a nine‐parent complete diallel, in two experiments differing in soil‐water availability after flowering. Weekly estimations of % GLA were made on 36 leaves per plot. Relative (%days) and absolute (m 2 days) GLAD and their components were derived from a fitted logistic function. The variances in both relative and absolute GLAD were each fully ( R 2 > 0.96) accounted for by their components. In spite of significant genotype × environment interactions for the component traits, the expression of heterosis for non‐senescence as related to the stay‐green trait was stable across experiments. The inheritance of the onset of senescence was additive, but a slow senescence rate was dominant over a fast rate. Consequently, a large relative GLAD (slow senescence) was partially dominant over a small relative GLAD. Because of the dominance of a large leaf area at flowering, the partial dominance in relative GLAD translated into overdominance for a large absolute GLAD. These results offer an opportunity for improving drought tolerance of sorghum in environments with post‐flowering drought stress.