Introgression of pink bollworm resistance from wild Gossypium thurberi Tod. to cultivated Gossypium arboreum L. cotton: pre-breeding efforts

Pink bollworm (PBW, Pectinophora gossypiella Saund.) is a pest of economic importance in cotton producing countries. Earlier results of host-plant resistance to the PBW indicated races of Gossypium hirsutum L. and some wild species including Gossypium thurberi Tod. which are resistant to PBW. Hence prebreeding efforts were made to transfer PBW resistance from G. thurberi to G. arborum. F₁, F₂ and BC₁ populations along with parents were studied for morphological, boll anatomical characters and infestation by PBW larvae. The F₁, F₂ and BC₁ generations were distinct from both the parents for all morphological characters. The highest boll toughness was found in G. thurberi, followed by F₁, whereas it was lowest in G. arboreum. Significant negative correlation was found between toughness with locule damage by PBW larvae. Promising prebreeding material is identified which will be excellent source of developing lines combined with PBW resistance, fibre strength and drought tolerance.