Genetic Analyses of Resistance to Fusarium Basal Rot in Onion

Fusarium basal rot (FBR) is a serious disease of onion (Allium cepa). We identified sources of FBR resistance, assessed efficacy of selection for increased resistance, and investigated its genetic control. Onion accessions were evaluated for FBR resistance, and percentage survival ranged from 0% to 78%. Survivors were intercrossed, and progenies from one cycle of selection showed increased survival by 18% to 52%. Selections were crossed to male-sterile lines, and hybrids showed specific combining ability for FBR resistance. Segregating families were produced, and quantitative trait loci (QTLs) were identified on chromosomes 2 and 4 conditioning FBR resistance. A second QTL on chromosome 4 was identified that decreased FBR resistance. Plants from families with different genotypes across the 1.5 logarithm of odds (LOD) regions on chromosomes 2 and 4 were self-pollinated, and resulting families were evaluated for FBR survival. Genomic regions on chromosomes 2 and 4 associated with resistance were validated at p = 0.05 and 0.10, respectively. The region on chromosome 4 associated with increased susceptibility was validated at p = 0.05. These results are in agreement with previous studies reporting high heritability and specific combining ability for FBR resistance and should be useful for selection of FBR-resistant onion.

General and specific combining ability studies of yield and yield character of sweet potato weevil in predominant and non-predominant environments

Combining ability for marketable sweet potato root yield were carried out using ten sweet potato varieties and their F1 hybrids in Cylasformicarius endemic (Landmark University, Omu Aran) and free (University of Ibadan) environments during 2012 cropping season. Both general combining ability and specific combining ability play significant role on traits such as marketable root yield, non- marketable root yield, and total number of storage root/plant and marketable storage root, root size, percentage of tuber damage and weight of total roots, as well as the incidence and severity were generally low, suggesting the role of additive and dominant gene action in tolerances to Cylasformicarius. Hybrids from the parents Resisto, TIS 87/0087 displayed high performance in term of Cylasformicarius tolerance. These parents and their hybrids appeared to have gene pools for Cylasformicarius tolerance that can be manipulated for developing promising hybrids in South west, Nigeria.

Combining Ability in Pearl Millet for Yield and Yield Attributing Characters

The experimental material comprised of thirty two crosses along with twelve parents (four lines and eight testers) and standard checks AHB 1200 Fe and AHB 1269. The experiment was laid out in Randomized Block Design with two replications. The observations were recorded on ten characters viz., days to 50 per cent flowering, days to maturity, plant height, number of effective tillers, earhead length, earhead head girth, downey mildew, 1000 grain weight, grain yield and fodder yield. The estimates of GCA effects revealed that most of the hybrids exhibiting higher grain yield than the standard hybrid check AHB 1200 Fe and AHB 1269 were based on two females viz., ICMA 91444 and ICMA 00888, and involved based on males viz., AUBI 15308 and AUBI 15615. The studies on specific combining ability (SCA) effects, it was observed ICMA 91444 x AUBI 15157 was observed the best specific combination for the trait grain yield.

Construction of Complete Diallel Crosses Plans

In this paper Complete Diallel Crosses (CDC) plan is constructed using two Balanced Incomplete Block Designs and the Galois field with the same set of parametersI. The designs were isomorphic on each other and the crossing is made between the lines. The analysis of CDC plans to estimate the general combining ability (GCA) effects and specific combining ability (SCA) effects were excluded from the model. The efficiency value of the constructed CDC plan is tends to 1, and universally optimum when v is very large. The construction is also illustrated with the suitable example.

General and specific combining ability of cotton germplasm in Mozambique using circulant dialells

The genetic diversity of species is an important way to maintain the natural capacity to respond to climate change and all stresses. This study aimed to estimate the general combining ability (GCA) and the specific combining ability (SCA) of the characteristics among 41 cotton cultivars and 9 inbred lines using circulant diallel. In 2016, 41 cultivars and 9 inbred lines and 75 hybrid combinations were evaluated at the Namialo Cotton Research and Seed and Multiplication Centre in the Meconta District, Nampula province. The experimental design was Federer's augmented blocks with four repetitions. The evaluated characteristics were: days for 50% of flowering (DAFlw), days for 50% of fruiting (DAFrut), plant height, average number of bolls (AnB), seed cotton yield in kilograms per hectare (Yield) and the mass of one hundred seeds (M100). The algorithm for establishing diallel crosses was based on Kempthorne and Curnow, where S was equal to 3. There was a predominance of non-additive effects for all characteristics analysed. The genotypes ALBAR FQ 902, IRMA 12-43 and MARICO showed greater additive effects for DAFlw, DAFrut, AnB, Yield and, M100

General and Specific Combining Ability in Sesame (Sesamum indicum L.) for Seed Yield and Related Traits

Combining ability study on seed yield per plant from a 7x 7 half-diallel cross of sesame over two years showed that both general combining ability (gca) and specific combining ability (sca) variances important for controlling the traits. Thus, the objectives of this study were to evaluate the gene action and select appropriate parents/crosses using combining ability analysis. Both additive and non additive was of greater significance for seed yield per plant, capsules per plant, days to flowering and oil content. Non additive genetic variances were in the genetic for 1000 seed weight and branches per plant. On the contrary preponderance of additive genetic was found in the inheritance of capsule length and seeds per capsule. The relative magnitude non-additive year interaction was larger than additive x year interaction. The variety Suprava was the best general combiner for seed yield and its major components except oil content. The cross combinations Suprava x Savitri, Suprava x JLT 408 and EC 90 x Savitri would be the best choices for obtaining desirable recombinants. Suprava x Savitri having additive gene control emerged as the best specific combiner for yield and its components except oil content. For improving seed yield and oil content simultaneously, the specific combiner IC 59 x Savitri was identified to be ideal as this cross mostly controlled by additive gene action and hence desirable recombinants can be obtained in early segregating generation. Breeding strategy for different crosses has been discussed in details. The information could help sesame breeders for appropriate selection of parents with high yield potential and oil content to develop future hybridization programs.

STUDYING OF COMBINING ABILITY OF SUNFLOWER (HELIANTHUS ANNUUS L.) BY A HEAD SQUARE AND SEEDS YIELD IN TESTER CROSSES

We analyzed a calculation of combining ability (CA) of 21 sunflower genotypes of Russian and foreign breeding by seed yield and head square, determined in a scheme of top-cross. Also there is considered a relation of mean squires of variability of common and specific combining abilities with a purpose to determine prevailing effects of gens. We revealed the sunflower variety samples with high meanings of effects of common combining ability and dispersion of specific combining ability as well as hybrid combinations F1 with high effects of specific combining ability.

Estimation of the specific combining ability (SCA) of eight bitter gourd (Momordica charantia L.) inbred lines in the sixth generation

Estimating the Specific Combining Ability (SCA) of bitter gourd (Momordica charantia L.) inbred lines for breeding F1 hybrid cultivars was performed at the Research and Development Center for Hi-tech Agriculture in Ho Chi Minh City from September to December 2019. The objective of the study was to select the outstanding hybrid combinations from diallen method to produce F1 hybrid cultivars. The results from estimating the SCAs based on the productivity characteristic of 28 hybrid combinations produced from eight bitter gourd I6 inbred lines (Q16, Q65, Q80, Q86, Q75, Q06, Q81 and Q87) following diallen method showed that four promised hybrid combinations (Q65/Q80, Q86/Q75, Q06/Q81 and Q81/Q87) performed over 10% higher SCA values and heterosis than the control, and they were less susceptible to infectious diseases. Fruit characteristics and yield of four hybrid combinations included fruit length of 16.0 to 17.6 cm; fruit width of 6.2 to 6.8 cm; 132.2 to 151.7 g/fruit and average yield of 4.1 to 4.3 tons/1000 m2.

Evaluation of the specific combining ability (SCA) for yield and brix of seven Cucumis melo. L inbred lines of the sixth generation

The objective of the experiment was to screen Cucumis melo L. inbred lines for high potential general combining ability and potential hybrids combinations for F1 hybridization. The experiment was conducted as a randomized complete block design (RCBD) with 29 treatments [21 hybrid combinations, control (TL3 hybrid) and seven Cucumis melo L. inbred lines I6], each with three replicates. Estimating the specific combining ability (SCA) of Cucumis melo L. inbred lines for breeding of F1 hybrid cultivars was carried out at the Research and Development Center for Hi-tech Agriculture in Ho Chi Minh City. Based on the specific combining ability of yield trait and total soluble solids (Brix) content of 21 hybrid lines from seven inbred lines following diallel method (Griffing 4 model), four potential hybrid lines (H41.6 x H58.6, H53.6 x H77.6, H32.6 x H41.6 and H53.6 x H58.6) yielded 10% higher than the control variety and gave fruits of oval shape, even fruit-net and low diseases infection.