ABSTRACT
Five new high glandulosity (HG) cotton strains that originated from a cross of La. HG 83-1-1546 X La. HG 1838-1497 and possessed a high frequency of medium size glands over the entire calyx, ovary walls and other plant parts were found to exhibit significant levels of resistance to natural field infestations of Heliothis spp. Resistance was measured by percent worm-damaged fruit, live larvae in fruit, and yield when compared with the susceptible Stoneville 213 cultivar-and the resistant La. HG 2058 experimental strain. The five new HG strains averaged 56 to 65 percent of the wormdamaged fruit and 51 to 71 percent of the number of larvae in fruit that was observed for Stoneville 213. Lint yields of the new HG strains generally were superior to Stoneville 213 in those tests that sustained economic damage from Heliothis spp. and generally were equal to this check in tests where economic damage from the pest was absent. The new HG strains were similar in resistance to La. HG 2058, but they reflected significant agronomic improvement over this check strain. Two strains, La. HG 810063 and La. HG 820660, are especially promising as genetically-enhanced bollworm-budworm resistant breeding stocks. They represent improvements in yield potential, earliness, fiber properties, plant size, and bract size while maintaining a moderately-high level of resistance to this pest complex.
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