Genetic Variability and Heritability for Resistance to Early Leafspot in Four Crosses of Virginia-Type Peanut
CC Green; JC Wynne
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Abstract: The potential for the development of large-seeded, high-yielding cultivars in peanut (Arachis hypogaea L.) with improved resistance to early leafspot (Cercospora arachidicola Hori) was determined in four crosses. A large-seeded, high-yielding cultivar (?NC 6?) was crossed to four small-seeded, low-yielding genotypes (PI 109839, PI 270806, PI 269685, and ‘Kanyoma’) with reported resistance to early leafspot. Estimates of additive and additive ? additive genetic variance for lesion count were determined for each cross and used to estimate narrow-sense heritabilities. Realized heritabilities were determined after one generation of selection among F5 lines for high and low lesion count. Additive genetic variance was greater than the additive ? additive genetic variance in the crosses NC 6 ? PI 109839, NC 6 ? PI 270806, and NC 6 ? PI 269685, whereas only additive ? additive genetic variance was found in the cross NC 6 ? Kanyoma. The variance-component heritability estimates were moderate to high for resistance to early leafspot, ranging from 0.41 to 0.78. Estimates of realized heritability, which ranged from 0.45 to 0.57, were similar to the variance-component estimates.