Short-Day Cotton Stocks as Possible Sources of Host Plant Resistance to the Pink Boll worm1

Abstract

An improvement of a previously used technique for screening cotton stocks for pink boll worm ( Pectinophora gossypiella (Saunders)) resistance was devised. The improved procedure involved the use of newly hatched pink boll worm larvae, rather than eggs, for infesting bolls of experimental stocks. Of the shortday stocks tested, Gossypium kirsutum race palmeri and G. hirsutum race marie-galante exhibited resistance to the pink bollworm. Further study indicated that the resistance of marie-galante was apparently due to the extensive proliferation of tissue in infested bolls which crushed, trapped or so injured the young larvae that death ensued. The resistance of marie-galante was categorized as antibiosis. The level of resistance occurring in Fl hybrids of marie-galante XDeltapine 15 suggested that the genetic characters responsible for resistance exhibited partial dominance in the cross to the susceptible stock.