Boll and fiber development in long staple upland cotton

Abstract

Cotton is the leading agronomic crop in Texas and is important to the agricultural productivity and economic vitality of regions where it is grown. The production of high quality lint under dryland conditions is becoming of increased importance. Texas is the leading state in dryland production of upland cotton. In 1998, 1.45 million hectares (~ 60 % of the state's total hectarage) of dryland cotton were planted in Texas (Texas Department of Agriculture, 1998). Dryland hetarage usually contributes to reduced yield and reduced fiber length, thus minimizing the profitability for the grower and the competitiveness of the fiber for the textile industry. For dryland cotton to remain a viable commodity for Texas producers its quality properties must meet the criteria of the textile industry and the demands set forth by the consumers, regardless of the stress environment encountered in most production regions of the state. Four experimental strains and three cultivars varying in fruiting pattern, boll maturation period, and average fiber length were studied under dryland and irrigated conditions in 1998 and 1999. The ANOVA indicated that UHM length varied across years and genotypes, but not irrigation. TAM 94L-25 and TAM 94M-14 had fibers longer that the other genotypes in 1998 and 1999. TAM 91C-95Ls and TAM 94M-14 had the longest fiber length development period of 26 days while Tamcot CAMD-E had the shortest duration of 24 days in 1998. In 1999, TAM 94L-25 had the longest fiber length development period of 34 days and Suregrow 125 had the shortest period of 26 days. In 1998, irrigation did not significantly influence the phenological development of either plants or the upper half-mean fiber length among these genotypes. While phenological development varied, P < 0.05, across genotypes, only VFIA, VFIB, and BMP varied, P < 0.05, across years. Boll maturation period had a significant genotype by year interaction. Also, boll maturation and the upper half-mean fiber length were positively correlated across both years. Since VFI and HFI are not increased, TAM 94L-25 and TAM 94M-14 require only about 5 additional days for fiber development than the 3 commercial cultivars.