General and specific combining ability for forage yield in lucerne (Medicago sativa)

1965 ◽  
Vol 16 (3) ◽  
pp. 293 ◽  
Author(s):  
H Daday

The genetic control of forage yields was investigated by a combining ability analysis based on a diallel cross made up of the hybrids between nine genotypes of lucerne. Summer forage yield was found to be controlled by additive and non-additive genes, and winter yield mainly by additive genes. General combining abilities differed markedly between genotypes for both summer and winter yields, and the correlation coefficient between summer and winter yields was high (0.89).Selected F2 and F3 progenies from crosses between Du Puits, Hairy Peruvian, and African cultivars substantially exceeded parental values for summer, winter, and spring forage production under row-sward conditions. There were positive correlations between summer, winter, and spring productivity in one of the two F2 experiments and in spaced F3 plants. Heritability estiniates for summer and winter yield ranged from 22 to 28%, and for spring yield, from 14 to 18%. On the basis of the estimated genetic parameters, yield increases should be obtained by either family selection or heterosis breeding.

2007 ◽  
Vol 58 (11) ◽  
pp. 1100 ◽  
Author(s):  
E. Piano ◽  
P. Annicchiarico ◽  
M. Romani ◽  
L. Pecetti

Finding the optimal parent number for synthetic varieties has a crucial importance in forage breeding. The objective of this work was exploring this number for Mediterranean tall fescue selected for forage yield. The general (GCA) and specific (SCA) combining ability of parents, and their effects on the performance and the inbreeding depression of synthetics, were also assessed. The full-sib families from the diallel cross of 20 genotypes chosen from well performing populations were evaluated for fresh biomass over 13 harvests in Sanluri (Sardinia, Italy). The Syn 1 and Syn 2 of 15 synthetics varying in parent number (4, 8, 12, 16 or 20) and, within same number, in mean GCA of parents were evaluated for dry matter yield over 11 harvests in Lodi (northern Italy) in a greenhouse simulating the temperature pattern of a Mediterranean environment. The yield responses of Syn 2 synthetics with 2 to 20 parents with highest mean GCA were predicted from yield values of S1 and F1 progenies, also evaluated in Lodi. The variance of GCA effects was almost 2-fold larger than that of SCA effects. The observed vigour loss from Syn 1 to Syn 2 of the 4-parent synthetics (−6%) tended to be greater than those of higher parent number groups. The 4-parent synthetics with larger SCA effects tended to greater inbreeding depression. The comparison among synthetics with different parent number and highest GCA of their parents indicated the superiority of the 4-parent synthetic over any other in both generations (P < 0.05). The predicted yield response was maximised by the 3-parent synthetic. The results and other considerations suggest adoption of 4- to 6-parent synthetics.


Genetika ◽  
2017 ◽  
Vol 49 (3) ◽  
pp. 1001-1014 ◽  
Author(s):  
Hasanalideh Haghighi ◽  
Ezatollah Farshadfar ◽  
Mehrzad Allahgholipour

In order to study the combining ability, genetic parameters and gene actions of yield, yield components and quality characters in rice, fifteen F2 generation of a 6?6 diallel cross, excluding reciprocals, was grown in a randomized complete block design (RCBD) with three replications. The results of analysis of variance showed significant differences between the genotypes for grain yield (GY), 100-grain weight (HGW), number of panicles per plant (PN), panicle length (PL), number of full grains per panicle (FGN) and for quality characters including amylose content (AC) and gel consistency (GC). The results of combining ability analysis revealed that general combining ability (GCA) and specific combining ability (SCA) were significant for characters GY, FGN, GC, AC, HGW and PN indicating the involvement of additive and non-additive effects in their inheritance, however high amounts of Bakers ratio remarked that additive gene effect had more portion in controlling these traits. The best combiners for GY, HGW, FGN, PN and PL, were RI18447-2, IR 50, Daylamani, RI18430-46 and Daylamani respectively. For AC and GC, the best combiner was Daylamani. Hayman's graphs showed that regression line passed below the origin cutting Wr axis in the negative region for HGW, PN, PL and GC, indicating the presence of over dominance. Estimates of genetic parameters showed significant amount of H1 and H2, and non-significant amount of D for the characters GY, PN, PL and GC, which confirmed the existence of dominance in the inheritance of these traits.


1971 ◽  
Vol 51 (5) ◽  
pp. 377-383 ◽  
Author(s):  
L. P. S. SPANGELO ◽  
R. WATKINS ◽  
C. S. HSU ◽  
S. O. FEJER

General and specific combining abilities were analyzed for total, marketable, early, and late yield, and for flower stalk number in a diallel cross of eight strawberry cultivars. Data were recorded from individual seedlings restricted to two runner plants, thereby eliminating variability resulting from differences in plant density. General and specific combining abilities for the five characters were highly significant. Estimates of general combining ability effects taken alone were, in general, of little value in predicting the order of desirability of individual crosses.


1979 ◽  
Vol 21 (1) ◽  
pp. 57-63 ◽  
Author(s):  
Wai-Koon Tan ◽  
Geok-Yong Tan ◽  
P. D. Walton

Twenty-one progenies and the parents of a 7 × 7 half diallel cross of smooth bromegrass (Bromus inermis Leyss.) were evaluated at four locations in Alberta in each of two years, for genetic variation and genetic by environment interactions in the expression of their yield potentials. Years, locations and their interactions were highly significant in the combined analysis of variance. Combining ability analysis revealed that general combining ability (GCA) and specific combining ability (SCA) were both important in the expression of yield, including spring, fall and annual yield, whereas GCA was more important than SCA for yield per area. Although the genotype × environment interactions were all highly significant, variation accounted for by combining ability effects was generally higher than the interaction effects of GCA and SCA respectively, with environments. High average GCA effects for spring, fall and annual yield were demonstrated for the clones UA5, UA9 and B42. These together with the high average SCA effects suggested that the three clones could be included in a synthetic to develop high yielding cultivars. The results suggested that recurrent selections involving multi-location and multi-year testing seems necessary in breeding for high yielding bromegrass cultivars in Alberta.


1983 ◽  
Vol 23 (121) ◽  
pp. 162 ◽  
Author(s):  
IM Wood

Grain and forage production of six accessions (Rongai, Highworth, T58/ 13, CPI 3 1 1 13, CPI 41 222 and CPI 60 216) of lablab bean (Lablab purpureus) were measured over two seasons in the Ord Irrigation Area. All accessions were quantitative short day plants, flowering during the early dry season (May-July). Forage yields at flowering were generally unaffected by sowing date for sowings made between December and February, but declined with later sowings. There were marked differences between accessions in the forage yield at flowering, and the peak yield of 8.6 t/ha was obtained with a December sowing of accessions T58/ 13; this comprised 3.6 t/ha of leaf containing 3.7% nitrogen and 5.0 t/ha of stem containing 1.1 % nitrogen. The uptake of nitrogen by the tops between sowing and flowering ranged up to 1.8 kg/ha.d (1 94 kg N in 108 days) indicating the potential value of lablab as a green manure crop. Grain yields ranged from 0.27 to 3.05 t/ha over all sowing dates and accessions with the peak yield being obtained in a February sowing of cv. Highworth. All accessions became smaller and bushier as sowing was delayed. This facilitated harvesting for grain. Cutting and removal of foliage at the onset of flowering led to rapid regrowth and renewed flowering, and gave grain yields up to 90% of those obtained from undefoliated treatments. The cultivar Highworth was best for grain production and for dual purpose forage and grain production.


1970 ◽  
Vol 50 (4) ◽  
pp. 439-444 ◽  
Author(s):  
L. P. S. SPANGELO ◽  
C. S. HSU ◽  
S. O. FEJER ◽  
R. WATKINS

Combining ability and interrelationships among four characters were studied in six gooseberry (Ribes grossularia) progenies produced by crossing each of two thornless to three large-fruited cultivars. Measurements were recorded for four consecutive years for fruit yield and 100-berry weight, and for one year for thorniness and plant height. General and specific combining abilities were significant and their interactions with years were not significant for fruit yield and berry weight, and general combining ability was significant for thorniness. Genotypic correlations agreed closely with the phenotypic correlations. Significant positive correlations were obtained between fruit yield with berry weight and plant height. The nonsignificant correlations between thorniness with fruit yield, berry weight and plant height suggest no genetic barrier to combining thornlessness with these traits.


1987 ◽  
Vol 40 (1) ◽  
pp. 57 ◽  
Author(s):  
BP Oldroyd ◽  
C Moran

Nine lines of honeybees were used to form a 9 x 9 partial diallel cross. Hamuli number was determined for samples of worker offspring. One set of workers was reared in non-maternal colonies which had been made uniform, as far as possible, with respect to colony strength (number of workers), while another set was sampled directly from the combs of each maternal colony. Combining ability analysis of variance revealed significant additive and non-additive genetic effects for both sets of data, regardless of whether inbred parentals were included or excluded from the analysis. Uniform rearing removed average heterosis and reciprocal effects.


1994 ◽  
Vol 21 (2) ◽  
pp. 112-115 ◽  
Author(s):  
D. W. Gorbet ◽  
R. L. Stanley ◽  
D. A. Knauft

Abstract Livestock production enterprises in the southern USA depend primarily on forage for feed. With the development of peanut (Arachis hypogaea L.) lines with good late leaf spot (Cercosporidium personatum (Berk. & Curt.) Deighton) resistance in the Florida breeding program, studies were initiated in 1983 at Marianna to evaluate their forage potential. Peanut breeding lines were grown without fungicide applications for leaf spot control and cuttings were made to evaluate forage production. Two forage cuttings were compared to a single cutting or harvest for each genotype. Pod yields were taken at the end of each season. Some lines produced dry matter forage yields exceeding 9000 kg ha-1 with two cuttings, with some single harvest yields exceeding 7000 kg ha-1. Significant differences were observed among genotypes, years, and forage harvest treatments. Two cuttings always produced the greatest forage yield but reduced pod yields as much as 50% for some entries. Some genotypes produced pod yields of 4000 kg ha-1 with the single forage harvest. Crude protein values for the forage were generally higher for two cuttings (14.0 − 19.6%), as compared to the single cutting or harvest (12.5 − 15.1%). In vitro organic matter digestibility (IVOMD) ranged from 59.6 − 72% for forage samples. These protein and digestibility values compare favorably to alfalfa (Medicago sativa L.) and perennial rhizoma peanut cultivars of A. glabrata Benth.


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