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Heritability of Carbon Isotope Discrimination and Correlations with Earliness in Cowpea
Author(s) -
Menéndez Cristina M.,
Hall Anthony E.
Publication year - 1995
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/cropsci1995.0011183x003500030003x
Subject(s) - heritability , biology , transpiration , vigna , selection (genetic algorithm) , limiting , agronomy , crop , adaptation (eye) , horticulture , botany , evolutionary biology , mechanical engineering , photosynthesis , artificial intelligence , computer science , engineering , neuroscience
Drought is a major constraint limiting rainfed crop production in semiarid regions. Selection criteria for increasing transpiration efficiency (TE) may be useful for enhancing drought adaptation. Carbon isotope discrimination (∆) has been negatively correlated with TE in cowpea [ Vigna unguiculata (L.) Walp.] and several other C 3 species. However, the realized heritability of ∆ is not known and ∆ has shown negative associations with days to flowering, which could limit its usefulness as a selection criterion for enhancing drought adaptation. Field studies were undertaken to estimate the heritability of ∆, estimate the genetic correlation between ∆ and earliness, and determine the response to selection for high and low ∆ and for earliness and lateness in two cowpea populations. Broad‐sense heritabilities were low to intermediate (0.27 and 0.58) for ∆ and high (0.72 and 0.80) for days to first flower (DFF). Selections were made among individual F 2 plants, and selected progenies were evaluated as F 3 and F 4 families. Realized heritabilities were low for ∆ (0.25–0.31) but significant and high for DFF (0.89–0.96). Selecting individual F 2 plants for high and low ∆ was effective in identifying F 3 and F 4 families with high and low ∆ only in one of the crosses. Genetic correlations between ∆ and earliness were negative and low to intermediate in magnitude (−0.14 to −0.66). Selection for earliness can be effective in the F 2 generation, but it may result in some indirect selection for high ∆ and, therefore, low TE. Selection for low ∆ may be most efficient with advanced families.