Original Article | 2002, Vol.24, No.4, pp. 555-560
Heritabilities and correlations for late leafspot resistance and agronomic traits in peanut (Arachis hypogaea L.)
Thinnakorn Kormsa-art, Sanun Jogloy, Sopone Wongkaew and Kamol Lertrat
pp. 555 - 560
Abstract
Late leafspot (Phaeoisariopsis personata (Berk. & M.A. Curtis) van Arx) is one of the most serious diseases of peanut. Although fungicide application is effective in controlling the disease, its high cost is considered uneconomical in many developing countries. In this situation, the use of resistant cultivars offers a better alternative. The objective of this study was to determine the heritability parameters of late leafspot resistance and agronomic traits and also to estimate correlations among the two parameters. Breeding materials including F2 of crosses between Tainan 9 × RLRS 15, Lampang × RLRS 15 and Khon Kaen 60-1 × RLRS 15, three backcrosses to female parent and three to male parent were planted in a RCBD with 4 replications at Khon Kaen University Farm. Natural infection of late leafspot was allowed. Disease score, lesion number, lesion size and spore production were reccorded as the resistance parameters. Pod yield, seed yield, pods number/plant, pod length, 100-seed weight and shelling percentage were also measured. Heritability estimates were generally low for all resistance parameters except for lesion size in crosses Lampang × RLRS 15 and Khon Kaen 60-1 × RLRS 15 and sporulation in cross Tainan 9 × RLRS 15. This suggested that selection in early generation based on phenotype of individual plants would be ineffective, except for lesion size in these crosses and spore production in cross Tainan 9 × RLRS 15. Heritability estimates were low for all of agronomic traits, except for pod number per plant in crosses Tainan 9 × RLRS 15 and Lampang × RLRS 15 and seed yield in cross Khon Kaen 60-1 × RLRS 15. This suggested that selection of individual plants would be ineffective, except for pods per plant in crosses Tainan 9 × RLRS 15 and Lampang × RLRS 15 and seed yield in cross Khon Kaen 60-1 × RLRS 15. Most components for disease resistance and agronomic traits showed low correlations among each other. The results indicate that selection of individuals with high heritable resistant traits such as for small lesion size and little sporulation would not affect the agronomic traits.
