Combining Ability Studies Research Articles

Leaf yield component combining abilities in mulberry (Morus spp.)

A line × tester analysis was carried out in mulberry (Morus spp.) to determine the genetic interaction in the expression of various quantitative characters including leaf yield. Eight clonal varieties were selected, 3 of them were designated as lines (♀) viz. Berhampore-1, China white and MS-5 and 5 of them were called as testers (♂) viz. Mandalaya, Kosen, Assamjati, MS-1 and Kajli. Combining ability studies were conducted on these parents along with their F1 hybrids for the variables laminar index, growth rate, weight of 100 dry leaves, number of primary branches per plant, plant height, nodal distance, leaf-twig ratio, aerial biomass, moisture content, moisture retention capacity and leaf yield. Broad genetic variability was observed among the genotypes. The ratio of General Combining Ability (GCA) and Specific Combining Ability (SCA) indicated the predominance of non-additive genes in mulberry. While China white (female) and MS-1 (male) were the best general combiners among the parents, Berhampore-1 × Kajli was the best cross for leaf yield. Results suggest that selective crossing followed by proper screening may be the best approach for breeding of high yielding varieties in mulberry.

COMBINING ABILITY FOR GRAIN TRAITS IN RICE

Combining ability studies in rice for grain traits revealed additive gene action for 100 grain weight, grain length, breadth and thickness. Based on the per se performance and gea effects, ADT 39 and Improved White Ponni were the best parents for improvement of grain traits besides grain yield. ADT 39/Pusa Basmati I and Improved White Ponni/Pusa Basmati 1 are suitable for 1 recombination breeding, while IR 50/Pusa Basmati I may be exploited for heterosis breeding.

HETEROSIS AND COMBINING ABILITY FOR GRAIN CHARACTERS IN RICE

Heterosis and combining ability studies were made on ten grain characters viz., kernel length, kernel breadth, kernel thickness, L/B ratio, kernel length after cooking, kernel breadth after cooking, linear elogation ratio, breadth wise elongation ratio, hulling per cent and milling per cent. The study revealed that the parents IR 50 and White Ponni possessed significant per se performance and gea effect for physical grain quality characters. The parents TKM 9 and ADT 37 are best adjuded for improving the cooking quality. The hybrid combinations ADT 37/White Ponni, TKM 9/White Ponni and ADT 39/ ADT 40 can be exploited for heterosis breeding. ADT 39 proved to be a good donor for improving the hulling and milling per cent. The high GCA variance for most of the characters indicate the predominance of additive gene action

HETEROSIS AND COMBINING ABILITY STUDIES IN SOME NON-RESTORER AND RESTORER LINES OF PEARL MILLET (Pennisetum americanum (L) LEEKE).

Investigations were carried out to estimate the extent of heterosis and combining ability in two sets consisting of eight non restorers viz., ICMS 81 B. L 111 B, J 126D2B, Tift 23D2B, Tift 239 D2B, MS 51418, PT 248/5B and PT 732/2B and eight restorers viz. PT 1824, PT 1921, PT 2584, PT 2598, PT 2784, PT 3095, K-560 and J 104 in pearl millet. Diallel crosses without reciprocals were effected in each set seperately. Most of the hybrid combinations exhibited significant heterosis for majority of the characters in both the sets. In grain yield, the hybrids L 1118 x J 126D2B and K 560 x PT 1824 exhibited the highest significant heterosis of 97.45 percent and 52.56 percent over the better parents in set I and II respectively. In combining ability studies, the variances due to genotypes and the hybrids were significant for all the characters in set I, while in set II, the variances due to hybrids were not significant in respect of panicle width and leaf width. For grain yield, the ratio of general combining ability to specific combining ability was 0.28: 1 in set 1, while in set II the ratio was 0.34: 1.

STUDIES ON COMBINING ABILITY IN SUNFLOWER (HELIANTHUS ANNUUS. L)

Combining ability studies in sunflower revealed that additive gene action was predominant for all the characters except 100 seed weight and oil content. Among the female parents, EC 85820 and EC 69874 were the best general combiners for earliness, K 74 for seed yield and EC 93617 for oil content. The tester parents K 1 and Co 1 were the best general combiners for seed yield and oil content respectively. The best cross combinations for seed yield were EC 75272 x K 2 and Kanpur Selection x Co 1, while for oil content it was EC 93617 x Co 1. In general there was no correspondence between mean performance and sca effects of the crosses.

COMBING ABILITY AND INHERITANCE STUDIES IN COWPEA (Vigna unguiclata (L.) Walp.)

In a six parent diallel cross in cowpea, the combining ability studies revealed hat both the additive and non-additive gene effects were important for plant height, ranches plant, clusters plant, pods plant, pod length, seeds pod, 100 seed weight nd yield plant. The cultivars Co4, EC 164370 and EC 170777 were the best general ombiners on the basis of their gca effects. Components of variance analysis revealed hat non-dditive effects were preponderant for the characters except pod length. liparental mating system was suggested for the improvement of cowpea.

COMBINING ABILITY IN GREENGRAM (VIGNA RADIATA (L.) WILCZEK)

In a 7 x 7 diallel cross in groengram, the combining ability studies revealed that both the additive and non-additive gene action were important for plant height, clusters per plant, pods per plant, seeds per pod and seed yield and the additive gene action was predominent for plant height and seed yield. For pod. length, only additive gene action was important. The parent PIMS 1 was good general combiner for seed yield, pod length and seeds per pod; the parent ML 65 was good combiner for seed yield and clusters per plant and KM 1 for plant height and pod length. The crosses KM 1 x PIMS 1, KM 1 x ML 65 and PIMS 1 x S 8 were found to be best combinations for most of the yield components. Biparental mating system was suggested for the improvement of greengram.

Heterosis and Combining Ability Studies and Relationship Among Fruit and Seed Characters in Peanut1

Abstract F1 progenies from an 8 × 8 full diallel cross were studied for the inheritance of fruit yield and fruit and seed characters which are important in peanut (Arachis hypogaea L.) quality breeding. Substantial genetic variaton was observed for most characters among parents and crosses. Presence of significant heterotic crosses for several characters was an indication of genetic diversity present among the parental lines. Whereas fruit and seed traits were controlled largely by additive genetic effects and fruits/plant and fruit weight/plant by nonadditive genetic effects, for shelling percentage both were equally important. Estimates of general combining ability (gca) for ICGV 86564 was best for various fruit and seed traits. Other genotypes with good gca were ICG 2379 and ICG 3043 for fruit weight/plant and ICGV 87123 for shelling percentage. ICG 4906, ICG 7360, and ICGV 86564 showed significant maternal effects for various traits. Significant maternal interaction effect was evident for more than six traits in six crosses. A positive association among fruit and seed traits, and of fruit weight/plant with fruit number and with fruit/seed length and width should result in progenies with larger fruit/seed size coupled with increased yields.

STUDIES ON COMBINING ABILITY FOR GRAIN PROTEIN AND LYSINE CONTENTS IN DURUM WHEAT

Combining ability study was carried out for protein and lysine contents in i dintiel set of five durum wheat (Triticum durum Desf.) strains. General as well a specific combining ability variances were highly significant for both the traits. How ever, the magnitude of GCA variances was higher than that of SCA varinces fo both the characters reflecting the predominance of additive gene effects in the gene tic control of these quality traits. The per se performance of the parer.ts was as sociated with their GCA effects. The varieties, Raj 911 followed by MACS 9 were the good combiners for both protein and lysine contents. The cross Raj 911 X RCBD B could be exploited further for obtaining nutritionally high protein hybrids in durum wheat,

Combining ability analysis of oxalic acid, minerals and green fodder yield in pearl millet

Combining ability studies with respect to such green fodder quality characteristics as oxalic acid, calcium, sodium, potassium and green fodder yield were carried out in a 12 × 12 diallel cross set in pearl millet (Pennisetum typhoides (Burm) S. & H.). With regard to differential expression of gene effects, studies for quality traits were carried out in different seasons and on different plant parts. The relative proportions of general and specific combining variances indicated the preponderance of non-additive genetic variance. Parents possessing desirable fodder quality characteristics were identified on the basis of combining ability and per se performance, and selection criterion for crosses was discussed. It was recommended that leaf portion should be biochemically analysed and manipulated in an environment when the genes are expressed.

Combining ability analysis over environments in diallel crosses of linseed (Linum usitatissimum L.)

This paper reports on combining ability studies for yield and its component traits in diallel crosses involving ten ecogeographically and genetically diverse linseed (Linum usitatissimum L.) cultivars in the F2 generation over three locations. The general combining ability (GCA) and specific combining ability (SCA) mean squares were significant at all three locations for all traits. Combined analysis over locations showed the same trend of significance. The ratio of GCA to SCA mean squares was significant for all the traits in individual location analysis as well as in combined analysis. This indicated the predominant role of additive gene effects in the inheritance of these characters. The GCA mean squares were several times larger than SCA mean squares for all the traits, indicating the presence of considerable magnitude of additive genetic variance and the additive x additive components of the epistatic variance. Consequently, effective selection should be possible within these F2 populations for all characters. Significant genotype-location and GCA-location interactions indicated that more than one test location is required to obtain reliable information. The inexpensive and reliable procedure used for making the choice of parents was the determination of breeding values of the parents on the relative performance of their F2 progeny bulks.

Combining ability analysis of beta-Carotene, total carotenoids and other grain characteristics in pearl millet

Combining ability studies with respect to grain quality characteristics viz., beta-Carotene, total carotenoids, protein content, 250-grain weight, grain hardness and grain yield were carried out from a 13x13 diallel cross set in pearl millet [Pennisetum typhoides (Burm S&H)].The parents versus hybrids comparison indicated significant heterosis for all the traits under study. In general the hybrids having higher grain yield had bold hard grains with more carotene but low protein content, although a few hybrids combined high yield with an average protein percentage. The relative proportions of the general and specific combining ability variances indicated predominance of non-additive genetic variance with respect to all the traits. The per se performance of parents provided a fairly good indication of their combining ability in most cases. Parents possessing desirable grain quality characteristics were identified. Breeding implications are discussed.

Combining ability analysis over F1-F5 generations in diallel crosses of bread wheat

Combining ability studies for grain yield and its primary component traits in diallel crosses involving seven diverse wheat cultivars of bread wheat (Triticum aestivum L.) over generations F1-F5 are reported. The general and specific combining ability variances were significant in all generations for all the traits except specific combining ability variance for number of spikes per plant in the F5. The ratio of general to specific combining ability variances was significant for all the traits except grain yield in all the generations. This indicated an equal role of additive and non-additive gene effects in the inheritance of grain yield, and the predominance of the former for its component traits. The presence of significant specific combining ability variances in even the advanced generations may be the result of an additive x additive type of epistasis or evolutionary divergence among progenies in the same parental array. The relative breeding values of the parental varieties, as indicated by their general combining ability effects, did not vary much over the generations. The cheap and reliable procedure observed for making the choice of parents, selecting hybrids and predicting advanced generation (F5) bulk hybrid performance was the determination of breeding values of the parents on the relative performance of their F2 progeny bulks.