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New Evidence Relating the Pilose Allele and Micronaire Reading in Cotton
Author(s) -
Kloth R. H.
Publication year - 1993
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1993.0011183x003300040007x
Subject(s) - biology , lint , locus (genetics) , allele , gossypium hirsutum , hybrid , horticulture , botany , antirrhinum , heterosis , genetics , agronomy , gene , mutant , arabidopsis
Experiments were undertaken to determine whether close linkage between the pilose allele and a locus influencing cotton ( Gossypium hirsutum L.) fiber fineness had been misinterpreted as pleiotropy. Pilose ( T 1 ), the dominant allele to the t 1 locus, is phenotypically described by a high density of trichomes on the leaf surface, the presence of trichomes on the carpel wall, and increased micronaire. Two lines, 239‐17/6 and 250‐14/2, were derived from single plant selections of pilose plants in an ‘Empire’ genetic background. 239‐17/6 has atypically low micronaire readings. The 239‐17/6 line was crossed to 250‐ 14/2, a pilose, high‐micronaire line, and to lines carrying t 1 (normally pubescent) and T sm 1 (glabrous). The F 1 plants were selfed for F 2 and backcrossefl to t 1 and T sm 1 parents. Similar hybrids and backcrosses were made between 250‐14/2 and t 1 locus recessives. The agronomic performance and fiber traits of 239‐17/6, 250‐14/2, Empire, and FTA (low micronaire check) were measured for 2 yr in replicated experiments. Lint yield, lint percent, and the fiber traits of elongation, maturity, micronaire, perimeter, span length, strength, and wall thickness were measured. 239‐17/6 expressed a T 1 pilose phenotype. All 465 F 2 seedlings from 239‐17/6 × 250‐14/2 and reciprocal cross had tomentose leaves. The combined results from crosses of 239‐17/ 6 and 250‐14/2 with t 1 and T sm 1 , and backcrosses of F 1 to t 1 and T sm 1 demonstrated that 239‐17/6 and 250‐14/2 both carry T 1 . The fiber of 239‐17/6 was not distinguishable from the fiber of either Empire or FTA for the wall traits of maturity, micronaire, and wall thickness. 239‐17/6 was shown to have the T 1 phenotype and behave genetically like T 1 . Since T 1 was associated with both high and low micronaire readings, the pleiotropic effect of T 1 on micronaire appears unlikely. A more likely explanation is the T 1 is linked to a gene or block of genes that influence micronaire.