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Effects of Boll Pilosity on Some Traints of ‘Pima’ Cotton 1
Author(s) -
Lee Joshua A.
Publication year - 1986
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/cropsci1986.0011183x002600040023x
Subject(s) - lint , biology , trichome , gossypium barbadense , botany , population , cultivar , gossypium , horticulture , fiber crop , gossypium hirsutum , agronomy , demography , sociology
A genetic stock, E‐2, of ‘Pima’ cotton ( Gossypium barbadense L.), differs from commercial cultivars of Pima in that the leaves, stems, and fruit (boll) surfaces are densely pubescent, and the fiber is coarser. Because there is no evidence that dense pubescence on leaves and stems of Pima affects fiber traits other than grade, I questioned whether pubescent boll in Pima cotton is accompanied by coarse fiber, as with upland cotton ( G. hirsutum L.). The first step in testing that hypothesis was to cross E‐2 with the very pubescent, although glabrous‐fruited, stock, ‘Pima S‐5‐H’, and examine an F 2 population. All segregates displayed dense pubescence on leaves and stems but segregated for pubescence on bolls. Two contrasting phenotypes were selected for increase, F 2 plants with pubescent (F 2 ‐HB), and with glabrous bolls (F 2 ‐GB). These were grown in replicated experiments with Pima S‐5‐H (P‐S‐5‐H), commercial Pima S‐5 (P‐S‐5), E‐2 with pubescent fruits (E‐2‐HB), and E‐2 with glabrous fruits and stems (E‐2‐SS). The P‐S‐5 entries graded lowest in leaf pubescence, 9.3 trichomes per 1 cm transect of abaxial surface of leaf, with the remaining entries distributed from 16.1 to 17.1. The entries were also significantly higher in lint percentage than the remainder, and had significantly larger bolls. Fiber length measures, 2.5 and 50% span, were about the same for all entries. There were some significant differences in length uniformity index, lint tenacity, and elongation, but these did not relate to differences in density of pubescence on various plant parts. The two entries with pubescent bolls, E‐2‐HB and F 2 ‐HB, at 5.9 and 5.8, graded significantly higher in micronaire value (fiber perimeter) than the remaining entries at 5.0 to 5.3.