Combining Ability in Cotton for Resistance to Pink Bollworm1
- F. D. Wilson and
- B. W. George2
Seed damage by pink bollworm (PBW) (Pectinophora gossypiella Saunders), to cotton (Gossypium hirsutum L.) grown for 2 years at Tempe, Ariz. in insecticide-f~ee environments was determined in six parents and in all of their hybrid and reciprocal combinations. The six parents included two cultivars, ‘Deltapine 61’ and ‘Stoneville 256’, three primitive race stocks, Texas 31 (T-31), 55, and T-167, and an upland breeding stock of complex parentage, designated AET-5. The latter four p~rents had been selected for PBW resistance in earlier tests. Parents and hybrids grown in 1977 showed significant genetic variability only at the fourth of five harvest dates, whereas those grown in 1978 showed significant variability at all four hgrvest dates. For both years, at the only directly comparable harvest, general combining ability estimates (GCA) were significant for low seed damage in T-167 and AET-5 and significant for high seed damage in T-55. Significant effects from specific combining ability (SCA) were shown for six of the hybrid combinations for at least one harvest date. The combinations of most interest, cultivar ✕ T-167, cultivar ✕ AET-5, and T-167 ✕ AET-5, showed only GCA effects. Maternal effects were not significant. Significant reciprocal effects at two harvest dates were confined to two hybrid combinations. On the basis of GCA estimates, T-167 and AET-5 should each combine well for low seed damage.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © . .