Antixenosis and Antibiosis Determination to Bollworm (Heliothis virescens) in Seven Advanced Lines and Three Cultivars of Cotton (Gossypium hirsutum L.) in Argentina
Feb 14, 2019
Antixenosis to Heliothis virescens was evaluation in trials to test genetic resistance in three cultivars and seven advanced lines of cotton. Genotypes tested were: 1-Pora INTA, 2-Guazuncho2 INTA, 3- “okra leaf”, 4-”glandless”, 5-”without trichomes”, 6-”nectariless”, 7-”without trichomes - okra leaf”, 8-”frego bract”, 9-Deltapine 90 and a pool of 10 T-94 lines. Thirty six m2 cages, protected, with anti-aphid screens, were used. Ten pots were used per cage in a Latin square design and fifty mated females were released in each cage. Oviposition was recorded by counting eggs on leaves, shoots and bracts the morning after moths were released. Genotype differences in underleaf oviposition were significant (a=0.05), the least preferred being those without trichomes, with okra leaf or the combination of the two. Neonate larvae in individual test tubes were fed squares of each genotype to evaluate antibiosis. After seven days, larval weight, pupal weight, time to pupation and time to adult emergence were significantly different between genotypes. Larvae fed with genotypes 2 and 10 showed less larval and less pupal weight and those fed with genotype 1 showed longer time to pupal formation and adult emergence. This result showed that “Guazuncho2 INTA” and the “Pool of T-94 lines” to be the most antibiotic to H. virescens.