Volume 14, Issue 3 (5-2012)
Abstract
The present experiment was carried out to assess the general combining ability (GCA) and specific combining ability (SCA) of six important commercial cultivars of Gossypium hirsutum L. of Venezuela, viz., ‘Deltapine 16’, ‘Tamcot-SP-21’, ‘Cabuyare’, ‘Stoneville’, ‘Ospino’ and ‘Acala 90-1’ and their 15 F1 hybrids, respectively. The data were analyzed using Griffing’s Model I Method II. Significant differences were found for all traits evaluated, except for seeds per boll and bolls per plant. Combining ability analysis of variance revealed significant differences for GCA and SCA effects among the parents and hybrids for almost all traits except for seed cotton yield ha-1 and fiber % for GCA and boll set, seed yield, and fiber % for SCA. The results suggested the presence of additive and non-additive gene action for almost all of the traits. The ratio GCA/SCA ranged from 0.59 for fiber fineness to 5.14 for plant height. Cultivars with the best (desired) GCA effects were cv. Cabuyare for blooming initiation, seed yield, and fiber fineness; Stoneville for plant height, stem diameter, number of fruit branches, number of set flowers, and boll weight; Tamcot-SP-21 for boll set and fiber fineness; Deltapine 16 for plant height, 100-seed weight and fiber length; Ospino for fiber strength. Also, the results revealed that Stoneville was the best general combiner for most of the traits. Finally, the correlations among GCA effects of the parents showed negative and significant associations of boll set with plant height and positive and significant associations of fruit branches with plant height, boll weight, and number of set flowers; of set flowers with plant height and boll weight; and of plant height with stem diameter.
Volume 24, Issue 1 (1-2022)
Abstract
The use of diversity implies knowing characteristics and traits of interest in genetic resources. In forages, the ability to produce seeds is essential to the persistence of cultivars in livestock systems. To study the floral variability and seed yield, 17 genotypes of
Chloris gayana Kunth and 14 genotypes of
Cenchrus ciliaris L. were evaluated. These genotypes were characterized considering floral morphology and total seed yield parameters. A randomized complete block design with four replications was used. In
C. gayana, accessions 7757, 6631, 981 and 7757 presented the highest (P< 0.05) Number of Inflorescences per Plant (NIP, 26.43), number of Spikes per Inflorescence (S/I, 10.73), Weight of Thousand Seeds (WTS, 0.52 g) and Total Seed Production (
TSP, 235.69 kg ha-1), respectively. In C. ciliaris, accessions 15687 (28.67) and 1098 (24.33) presented the highest values (P< 0.05) for NIP. Accessions 777 (151.33) and 6642 (150.67) had the highest (P< 0.05) Number of Seeds by Inflorescences (NSI) and genotypes 6652 (0.238 g), 15687 (0.207 g), 16660 (0.215 g) had the highest (P< 0.05) Weight of one Hundred Seeds (WHS). Finally, accessions 6652 (210.93) and 1098 (188.55) had the highest (P< 0.05) TSP. The genotypes of C. gayana and C. ciliaris indicated an important morphology variation. Likewise, higher seed production, which is associated with genetic variability, can be an attribute to be considered during the selection of materials in forage breeding programs, as a complement to traditional evaluation characteristics.
