A quantitative genetic study of lint yield, earliness, lint percent, 2.5 and 50% span length, uniformity index, fiber fineness, and fiber strength was conducted in upland cotton, Gossypium hirsutum L., utilizing the Jinks‐Hayman diallel analysis. Ten selected lines and their 45 possible F1 combinations in 1969 and 1970, plus the 45 corresponding F2's in the second year, were included in randomized, replicated experiments at a single location.Analyses of variance indicated highly significant differences among entries for all traits in both years. Partial failures of the diallel assumptions were noted for each trait, although some traits did more nearly comply with those assumptions than did others. Epistasis was not detected as a significant factor for any of the traits. A genotype by environment interaction for the additive components of variation was observed for lint yield, lint percent, and 2.5% span length. The dominance relationships among parents were not constant over years for earliness, lint percent, 2.5% span length, fiber fineness, or fiber strength. Multiple allelism was shown by all traits except fiber fineness; however, gene correlations and parental heterozygosity were not (or could not be) detected for any trait.Overdominance governed lint yield, earliness, lint percent, 50% span length, and uniformity index. Partial dominance was operative for fiber fineness, and complete dominance was indicated for 2.5% span length and fiber strength. Narrow‐sense heritabilities indicated that mass selection should be effective for improving 2.5% span length, fiber fineness, and fiber strength among lines in this material and somewhat less effective for improving earliness, lint percent, 50% span length, and uniformity index. Alternatives, such as pedigrees, sib tests, and progeny tests, must be considered to achieve genetic progress for lint yield in this material.

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ABSTRACT'NF201' (Reg. No. CV-34, PI 674106) is a forage triticale (×Triticosecale Wittm.) with prolific growth habit and excellent fall-winter forage potential, developed by the Samuel Roberts Noble Foundation, Inc., Ardmore, OK, and released in 2013. NF201 was tested under the experimental designation, NF96210. NF201 was developed from the double cross NF83/'Stan II'//'Roughrider'/'Stan II' made in 1996. Individual plant selections were performed in early generations followed by head-row and progeny-row schemes. NF201 was selected on the basis of early fall-winter vegetative growth. It has a tall growth habit with an average plant height of 112.5 cm. The leaves are longer and narrower compared with the check cultivars. NF201 was developed mainly for fall-winter forage in the south-central United States. The fall-winter forage yield of NF201 was 9 and 20% more than the check cultivars TAMcale5019 and Thundercale, respectively, at the southern Oklahoma trials. In 2 yr of evaluations at Iowa Park, TX, the fall and winter yield of NF201 was 25 and 21% higher, respectively, than TAMcale5019. At Overton, TX, NF201 was superior to the check cultivars for early season yield. Forage quality of NF201 was similar to the check cultivars. Collectively, in the southcentral United States, NF201 had significantly higher yields in the fall-winter period compared with the check cultivars, suggesting that it is the best choice for producers who need forage for early fall-winter grazing.

Gardner's grid system was investigated relative to plant selection efficiency within an upland cotton (Gossypium hirsutum L.) cultivar known to be genetically variable for fiber length. A relatively small area, planted to ‘Westburn,’ was arbitrarily subdivided into three equalsized grids prior to harvest. One hundred individual plant selections were made in each grid on the basis of boll type and apparent yield. Then, based on fiber length, the upper and lower 10% of the plants were selected within each grid and over the area as a whole. Progeny row performances of the selected plants were obtained for fiber length in two environments. Phenotypic variances, selection differentials, selection responses, and heritabilities under the two procedures (grids vs. no grids) were then compared at the 5 and 10% levels of selection intensity.In this experiment, the grid method reduced phenotypic variation by 22%; lowered selection differentials by 11 to 14%; produced 20 to 35% greater selection responses; and estimated “realized” (i.e., narrow‐sense) heritabilities 41 to 52% higher than did the identical selection procedure without grids.Based on the results of this and other experiments and on the logic underlying the method, use of grids should increase the effectiveness of plant selection regardless of crop, quantitative trait, or breeding method employed, provided there is genetic and environmental variability in the material. The method appears particularly useful when the breeder attempts to discriminate among small, inconsistent differences (i.e., when heritability is low). Use of the technique was considered for areas larger or smaller than those utilized herein, as well as for selection among progeny rows.