Diallel Set Research Articles

Combining Ability Estimates in Arachis hypogaea L. I. F1 Seedling Responses in a Controlled Environment1

The feasibility of identifying superior parents of peanuts (Arachis hypogaea L.) by testing Fl hybrids grown under controlled conditions was investigated. Estimates of combining ability, maternal, and reciprocal effects among 15 F1 hybrids were determined for 17 seedling characters. Six lines of cultivated peanuts were crossed in all possible combinations to form a 6 × 6 complete diallel set. The lines included Valencia, Virginia, and Spanish types from three geographic regions of South America. Statistically significant variances were found for general combining ability for 11 of the 17 characters. Estimates of specific combining ability for three characters were statistically significant. The greatest portion of genetic variance was associated with general combining ability. Maternal and reciprocal effects were significant for two and one characters, respectively. Specific crosses among certain types had higher means than expected based on mid‐parent values for several characters.

Environment and genotype-environmental components of variability. VI. Diallel sets of crosses.

Environmental and genotype-environmental components of variability VI. Diallel sets of crosses

Relative importance of gene effects in bitter gourd (<i>Momordica charantia</i> L.)

Full diallel set was made in bitter gourd (Momordica charantia L.) involving six genetically divergent parents, namely BGGB1, BGGB4, BGGB6, BGGB12, BGGB13 and BGGB14 and their inheritance pattern of yield and yield contributing traits were studied. Â Key words: Diallel cross, Gene effect, Bitter gourd DOI = 10.3329/bjb.v36i2.1512 Bangladesh J. Bot. 36(2): 189-191, 2007 (December)

Combining ability for yield and yield contributing characters of white jute (<i>Corchorus capsularis</i> L.)

Crosses were made between three varieties and seven accessions of white jute (Corchorus capsularis L.) in all possible combinations to establish 10 × 10 full diallel set. Variances for general combining ability (GCA) and specific combining ability (SCA) were significant or highly significant for all the characters indicating additive and non-additive gene actions played predominant role for expression of these characters. The magnitudes of GCA variance were higher than the corresponding SCA variance confirmed the predominance of additive genetic variations for these traits. The variety CVL-1 and Acc. 1831 were good general combiners for plant height, technical height, base diameter, number of nodes, bark weight, fibre weight and stick weight. Crosses, var. CVL-1 × Acc. 1831, Accs. 3695 × 4087, Accs. 1831 × 1833, Accs.1831 × var.CC-45, Acc. 2146 × var. A-38 and Acc. 2146 × var.CC-45 revealed significant positive SCA effect for fibre weight. Significant reciprocal SCA effect was observed in crosses, Accs.1832 × 3695, Accs.1833 × 1831 and Acc. 4087 × var.CVL-1. Crosses, var. CVL-1 × Acc.1831, Accs. 3695 × 4087, Acc.1831 × var.CC-45, Acc.2146 × var.CC-45 and a reciprocal cross, Accs.1833 × 1831 were found to be good specific combiners for bark weight, fibre weight and stick weight. Key words: Combining ability; Fibre yield; White jute DOI: 10.3329/bjb.v39i1.5530Bangladesh J. Bot. 39(1): 79-85, 2010 (June)

Genetic Nature of the Concentration of 2,4‐dihydroxy‐7‐methoxy 2H‐l,4‐benzoxazin‐ 3(4H)‐one and Resistance to the European Corn Borer in a Diallel Set of Eleven Maize Inbreds1

A diallel set of 11 inbreds of maize, Zea mays L., was used to study the concentration of 2,4‐dihydroxy‐7‐methoxy‐ 2H‐l,4‐benzoxazin‐3 (4H)‐one (DIMBOA) in the whorl tissue and the resistance to leaf feeding by firstbrood European corn borers, Ostrinia nubilalis (Hubner). The correlation between concentration of the chemical in the plant tissues and level of resistance to leaf feeding by the first‐brood borer was highly significant statistically for the inbreds (r = −0.89**) and the single crosses (r = −0.74**). Also, effects due to general and specific combining ability were highly significant for both traits, but general combining ability accounted for 84% of the variation in the resistance ratings and for 91% of the variation due to concentration of DIMBOA. These results provide further evidence that DIMBOA is a chemical factor in the resistance of maize to the European corn borer and that an objective chemical analysis for DIMBOA in the whorl portion of the maize plant can serve as an indicator of resistance to leaf feeding by the first‐brood European corn borer and possibly eliminate the visual resistance ratings.

Combining Ability And Heterosis In Snakegourd (<i>Tricosanthes Cucurminata</i> L)

A half diallel set of five parents and their 10 F1’s were studied to determine the combining ability and magnitude of heterosis for eight important characters in snakegourd at the experimental field of Bangabandhu Sheikh Mujibur Rahman Agricultural University during April to July, 2004. Combining ability analysis revealed that both general and specific combining ability variances were significant for all the characters except fruit diameter and fruit yield per plant. Predominance of additive gene action was noted for all the characters except days to first female flower where non-additive gene action was predominant. Parent P1 was the best general combiner for fruit yield and some yield contributing characters. Among the crosses P2 X P3, P1 X P2 and P1 X P4 were the best specific combiner for fruit yield and some of yield contributing characters. Both positive and negative heterosis was obtained of which few hybrids showed desirable and significant values. P2 X P5 showed the highest significant mid parental heterotic value for earliness and high yield whereas, P1 X P2, P2 X P3, P2 X P5 and P3 X P4 showed the highest significant better parent heterotic effect for earliness and high yield. Key words: Snakegourd (Trichosanthes cucurminata L.); combining ability; heterosis; fruit yieldDOI: http://dx.doi.org/10.3329/bjpbg.v23i2.9318 Bangladesh J. Pl. Breed. Genet., 23(2): 1-6, 2010

A quantitative study of the inheritance of resistance to bacterial blight in Upland cotton

SUMMARYPopulations derived from a diallel set of crosses involving five inbred Upland varieties were tested for bacterial blight resistance at Wad Medani in the Sudan and at Namulonge in Uganda. Four of the varieties carried a knownBgene for resistance; noBgene was present in the fifth, which was used as a susceptible parent. The importance of genotype/environment interaction was emphasized and it was found that theBgenes did not maintain the same dominance relationships at the two sites.The Reba gene,B9L, segregated as a gene or ‘effective factor’ of large effect but Mendelian segregation was not discernible in hybrid populations not involving Reba. Most of the genetic variance was accounted for by additivity and dominance. Although statistical analysis failed to reveal epistasis there was a strong interaction in theB2×B6cross.At Namulonge, where it was possible to test for leaf and boll resistance, the proportion of dominant and recessive alleles was the same for both phases of the disease.

Combining Abilities and Relative Dominance among Maize Inbreds for Resistance to Earworm Injury1

General combining ability effects for corn earworm, Heliothis zea (Boddie), resistance were highly significant and accounted for approximately two‐thirds of the genetic variability measured in two sets of diallel crosses among sweet corn, Zea mays (L.)> inbreds. Specific combining ability estimates were generally low, though significant in one case. Highly significant genotype‐environment mean squares were attributed to the interaction of general combining ability with location and years. The relative importance of location effects was essentially equivalent to those for years.Trends among constant parent regression coefficients were essentially absent, suggesting a low level of dominance for resistance to earworm injury. Dominance estimates for individual inbreds and average estimates as obtained from variance component ratios for diallel sets were also in the partial dominance range. Estimates of heritability for selection of half‐sib families were .340 and .398 for the nine‐line and 12‐line sets, respectively. Although heritabilities of this size should make reasonable selection gains possible, culling F1's with large noncomplementing specific combining ability effects from selected half‐sib families of high general combining ability would further enhance potential selection gains.

Analysis of A Diallel Set of Early Flint Varieties of Maize1

We evaluated a diallel set of 10 early flint varieties of maize (Zea mays L.) for yield and seven other traits at two planting rates (85.8 and 128.7 M plants per ha) and dates (May 3 and June 14). Dates and rates showed differences; however, except for erect plants, the interactions of entries with the two planting rates and dates were not significant. The analyses showed that the initial evaluation of the varieties and their crosses could have been made in one cultural environment for this group of varieties.Highest average yields were obtained on the early planting date (May 3) at the high rate (128.7 M/ha). Average yields for both dates and rates were 2,536 and 4,167 kg/ha for the 10 varieties and 45 variety crosses, respectively. Saskatchewan was the highest yielding variety (3,119 kg/ha). ‘Syzldecka’ ✕ ‘Motto’ was the highest yielding variety cross (5,309 kg/ha). The crosses that included Motto as one of the parents had the highest average yields (4,312 kg/ha).Average heterosis was 43% relative to the high parent and 72% relative to the midparent. Only two of the crosses (‘Alberta’ #x2715; ‘Rutherford’ and ‘Morden’ ✕ ‘Pervenets’) were lower yielding than one of the parents. Average variety heterosis (mean of parents vs. mean of crosses) was 71%. The amount of heterosis observed in the variety crosses indicates that the parent varieties were genetically diverse.

Analysis of Two Diallel Sets of Sweet Corn Inbreds for Corn Earworm Injury 1

Analysis of Two Diallel Sets of Sweet Corn Inbreds for Corn Earworm Injury ¹

Resistance conferred by new gene combinations to bacterial blight of cotton

F2 families from a diallel set of crosses involving Sakel (Gossypium barbadense) strains homozygous for each of the B genes, B 1 to B 7, were screened for resistance to leaf infection by Xanthomonas malvacearum. B 2B6 was the most resistant, with B 1B4, B2B4, B3B6 and B 4B6 slightly less effective than B 2B6. Other gene combinations exhibiting additivity, but conferring intermediate resistance only, were B 1B3, B2B3, B3B4, B3B5, B4B5, B4B7, B5B6, and B 5B7. B 1 and B 4 were each transferred to the Upland variety Wilds Sus 16/1. The synthesis of normal homozygous B 1 Wilds revealed that the gene d b, one of two duplicate genes causing dwarfing, was not present in Wilds Sus 16/1. B 7 when transferred to Wilds Sus 16/1 and to Acala 4–42, both “susceptible” Uplands, was much more effective in the latter variety, emphasising the importance of genetical background on the expression of major genes for bacterial blight resistance.

The inheritance of the resistance of wheat to two races of Ustilago nuda

The inheritance of resistance to two races of Ustilago nuda was studied in a diallel set of crosses involving seven varieties of Triticum aestivum ssp. vulgare . Data from F 2 hybrid populations and F 2 plant progenies from test crosses to the variety Hybrid 46, susceptible to both races, indicate that the resistance is controlled by single dominant and independent genes. The symbol Ut is suggested to designate these genes. The major gene which controls seedling resistance of variety C.I. 12633 to Erysiphe graminis is found not to be associated with the two major genes that govern resistance to races C 1 and C 2 of U. nuda .

Inheritance of resistance to yellow rust ( Puccinia glumarum Erikss. & Henn.) in seven varieties of wheat

The inheritance of resistance to four physiologic races of Puccinia glumarum has been studied in seven varieties of wheat. Using an assessment of the rust reaction of seedling plants in the F1, F2 and F3 of a diallel set of crosses between these varieties, seven genes conferring resistance have been identified at four loci. In general, resistance was found to be inherited as a dominant character although cases of recessive inheritance, particularly against aggressive physiologic races of the pathogen, also occurred. A systematic nomenclature for the genes conferring yellow rust resistance is proposed, and it is suggested that new, and genetically distinct, differential host varieties should be produced for the identification of physiologic races of P. glumarum.

ESTIMATION OF THE COMPONENTS OF HETEROSIS

In previous papers (JINKS 19544,1956) the analysis of the parents, F,’s, F2’s and I backcross generations of an 8 x 8 diallel between inbred varieties of Nico- tiana rustica using the method of diallel analysis described by JINKS and HAY- MAN (1953), and extended by SINKS (1954), HAYMAN (1954), DICKINSON and JINKS (1956) and JINKS (1956) have been presented. They showed that non- allelic interactions, as well as additive and dominance effects, play an important role in the inheritance of all the three characters followed, namely, final height, time of flowering and leaf size. This finding was subsequently confirmed for a number of diallel sets of crosses in other species where a wide range of characters were followed (JINKS 1955; ALLARD 1956). What is more important to our pres- ent discussion, however, was the finding that the F, generation of crosses show- ing nonallelic interactions were in general superior in their performance to those of noninteracting crosses. This appears to implicate nonallelic interactions as a major source of heterosis, and we shall now attempt to assess the magnitude of their contribution relative to those of the other components of heterosis.