Heterotic Effects Research Articles

Selection of promising genotypes of lentil (Lens culinaris Medik.) by deciphering genetic diversity and trait association

A panel of fifty diverse genotypes of lentil were evaluated to assess the genetic diversity for 11 morpho-physiological attributes. The results revealed wide range of variability among the genotypes for the examined characteristics. The mean performance demonstrated that the best genotype for more than one trait viz., plot yield, yield/plant, Leaf Area Index (LAI), Crop Growth Rate (CGR), biomass and plant height was LL1384. Traits association approximation witnessed a positive and significant relationship of seed yield with most of the studied traits. Cluster analysis distributed genotypes into seven distinct clusters. Cluster III happened to be the largest comprising of 20 genotypes, followed by Cluster VII comprising of 9 genotypes. The maximum inter-cluster distance was perceived between clusters II and IV which suggests the possibility of high heterotic effect if cross will be made between the individuals of these clusters. The principal component analysis developed 11 Eigen vectors and, of these three principal components had explained about 82.50% of variations. The characters that had the highest weight in component first were plot yield, yield/plant, pods/plant, CGR, biomass/plant, LAI and plant height, which explained 57.03% of the total variance. The biplot results were in accordance with correlation estimation, indicating that indirect selection based on component traits would help in improving the seed yield in lentil. Hybridization among genetically diverse genotypes of different clusters would be helpful in broadening the genetic base as well as in the creation of desirable recombinants for developing new improved lentil varieties.

Estimation of Heterosis Combining and Ability in Faba Bean (Vicia faba L.) by Line X Tester Technique

The present study was conducted at Sakha Research Station during 2014/2015 and 2015/2016 growing seasons. Line x Tester analysis was used, five lines and four testers were crossed in all possible cross combination according to factorial mating design producing twenty hybrids of Faba Bean in the first season. All genetic materials were tested under two sowing dates, i.e. October 20 (early date) and November 20 (late date) each in one experiment arranged in a randomized complete block design with three replications in the second season. Results revealed highly significant variations within parents and F1 genotypes indicating a wide genetic variability for the studied characters and the possibility of genetic improvement using such genetic pools of faba bean. Regarding yield and its components traits, the most crosses exhibited significant positive heterosis values relative to better parent for total dry seed yield, three, six and four crosses exhibited significant positive heterotic effects relative to better parent for number of seeds/plant, seed yield/plant and 100-seed weight respectively, under the two sowing dates. Both general (GCA) and specific (SCA) combining ability were significant for the most studied characters revealing the important role of both additive and dominant components in the inheritance of the studied characters. The parental genotype (Giza716) was a good combiner for seed yield/plant and100-seed weight under the two sowing dates. Several crosses exhibited significantly positive SCA effects for the most studied characters especially the crosses (Sakha 4 x Qahera 4, Cross 957 x Giza 843 and Giza 716 x Qahera 4) and the crosses (Sakha1 x Misr 1, Sakha 4 x Misr 1 and Giza 40 x Giza 843) which exhibited highly significant and positive SCA effects for seed yield/plant and 100-seed weight respectively under the two sowing dates. Heritability in broad sense estimates (Hb %) were higher than their corresponding of narrow sense heritability (Hn %). The estimates of narrow sense heritability ranged were (37.7-40.4 %), (33.7-46.8 %) and (45.5-48.3 %) for number of seeds/plant, seed yield/plant and 100-seed weight, respectively under the two sowing dates.

THE ESTIMATION OF THE ECONOMIC USE AND LIFETIME PRODUCTIVITY OF COWS OF UKRAINIAN BLACK-AND-WHITE DAIRY BREED DEPENDING ON THE REASONS OF THEIR DISPOSAL

An important selection peculiarity of dairy cows is their productive longevity. Besides, the indicators of cow productivity along with genetic potential are the most important criteria of the economic efficiency of their use. Low or not sufficient level of lifetime productivity indicators and of the period of the economic use of cows determine the necessity of monitoring of the selection information according to these indicators in the breed herds as well as the of using corresponding selection methods for their improvement. The goal of our research was the estimation of an economic use of lifetime cow productivity of Ukrainian Black-and-White dairy breed depending on the reasons of their disposal from the herd and genotype. The research was conducted at a private agrarian firm (PAF) «Yerchyky» Zhytomyr oblast according to the data of breeding and productive use of 497 cows which were disposed from the herd on different reasons. The reasons for the cow disposal were determined according to the veterinary disposal acts. The indicators of cow economic use and lifetime productivity were determined on the ground of the term of rearing, life duration, term of economic use, amount of lactations, the total duration of lactation period, milk yields, milk yield per one lactation day, per life, and per economic use. Statistical processing was performed by means of Microsoft Excel software kit using the methods of variation statistics. As follows from the results of the research, in the process of holsteinization the dynamics of the parameters of the economic use of cows is characterized by curvilineal type: as follows from the heterotic effect they increased in animals with an conditional share of genetic heredity of Holstein breed from 50 and 62.5 to 75%, and then when the genetic heredity share of the improved breed increased by more than 75% they got worse due to the contradiction “genotype-environment”. At the same time within the determined genotypes (1st group-up to 50%, 5th group-87.6–100%) the indicators of lifetime productivity increase in case of 66% of reliable results. Besides, the interconnection level of the indices of lifetime use of the dairy cows of different genotypes has been studied. The criteria of the significance of the correlation coefficients according to Student has been used. The closer the linkage, the higher the correlation coefficients and the higher the criteria of their reliability. Generalized criteria of reliability on the grounds of all indicators of lifetime use was the lowest in cows of the 1st and 2nd groups, and the highest in cows of the 3rd group with further decrease in high half-bred cows and pure-breed cows of the 4th and 5th groups. It testifies to the fact that there is a close interconnection between given parameters and real milk yields in 3rd group cows (62.6–75.0% of the improved Holstein breed). At present, the reason of the shortening of the period of economic use is an early disposal of cows from the herd. A greater part of milking cows is disposed in the most productive period or even before it. At the given enterprise, a vast majority of holsteinized cows (77.5%) was disposed from the herd on four main reasons: unsatisfactory reproductive capability (32.2%), limbs diseases (22.3%), postpartal complications (13.9%) and low productivity (9.1%). The other reasons for cow disposal were within 1.6–7.0% (totaled up 22.5%) as to the total number of cow population that were disposed of the herd. It should be mentioned that the disposal caused by low productivity was only in the first calvers of the 1st and 2nd groups, in which the conditional share of genetic heredity of a Holstein breed did not exceed 62.5%. The parameters of the economic use and of lifetime productivity of Ukrainian Black-and-White dairy cows of different genotypes which were disposed of the herd because of their unsatisfactory reproductive capability, limbs diseases, postpartal complications and low milking productivity have been also analyzed. It has been determined that the indicated reasons for the disposal had different effects on the parameters of an economic use and on cow productivity. Because of any of four indicated reasons for cow disposal of the herd under condition of in-barn keeping and optimal feeding the preference on lifetime productivity belongs to the cows of the 4th and 5th groups (with a conditional share of Holstein heredity of more than 75%) with simultaneous worsening of the indicators of economic use. As a third part of cows at this enterprise was disposed of the herd ahead of time on the reason of unsatisfactory reproductive capability, that results in breeding value and in the results of the economic use of cows, the updating of the technology of artificial animal insemination and renewal will promote to solving the problem.

Evaluation of maize inbred lines and topcross progeny for resistance to pre-harvest aflatoxin contamination

Pre-harvest aflatoxin contamination occurs in maize following kernel colonization by Aspergillus flavus. Aflatoxin contamination resistance is a highly desired trait in maize breeding programs. The identification of novel sources of resistance to pre-harvest aflatoxin contamination is a major focus in germplasm screening efforts. Here, we performed a field evaluation of 64 inbred lines over two years for pre-harvest aflatoxin contamination. Topcrosses were also performed with two testers, B73 and Mo17, to generate 128 F1 hybrids which were also evaluated over two years. Hybrid performance was used to calculate both general combining ability (GCA) of the inbreds, and observed heterosis for aflatoxin resistance. Over both years of the study, aflatoxin concentrations ranged from 80 ± 47 to 17,617 ± 8816 μg kg−1 for inbreds, and from 58 ± 39 to 2771 ± 780 μg kg−1 for hybrids with significant variation between years and lines. The inbred lines CML52, CML69, CML247, GT-603, GEMS-0005, Hi63, Hp301, and M37 W showed <1000 μg kg−1 of aflatoxin accumulation in both years of the study and less than the resistant check, Mp313E, in at least one season. Among these, CML52, GT-603, and Hi63 also showed significant GCA with the testers in hybrid progeny. CML52, GT-603, and M37 W also showed heterotic effects of −13.64%, −12.47%, and − 24.50%, respectively, with B73 resulting in reduced aflatoxin contamination. GT-603 also showed a similar heterotic effect for aflatoxin contamination, −13.11%, with Mo17 indicating that this line may serve as a versatile source of aflatoxin contamination resistance in breeding programs.

Drought stress has transgenerational effects on seeds and seedlings in winter oilseed rape (Brassica napus L.)

BackgroundDrought stress has a negative effect on both seed yield and seed quality in Brassica napus (oilseed rape, canola). Here we show that while drought impairs the maternal plant performance, it also increases the vigour of progeny of stressed maternal plants. We investigated the transgenerational influence of abiotic stress by detailed analysis of yield, seed quality, and seedling performance on a growth-related and metabolic level. Seeds of eight diverse winter oilseed rape genotypes were generated under well-watered and drought stress conditions under controlled-environment conditions in large plant containers.ResultsWe found a decrease in seed quality in seeds derived from mother plants that were exposed to drought stress. At the same time, the seeds that developed under stress conditions showed higher seedling vigour compared to non-stressed controls.This effect on seed quality and seedling vigour was found to be independent of maternal plant yield performance.ConclusionsDrought stress has a positive transgenerational effect on seedling vigour. Three potential causes for stress-induced improvement of seedling vigour are discussed: (1) Heterotic effects caused by a tendency towards a higher outcrossing rate in response to stress; (2) an altered reservoir of seed storage metabolites to which the seedling resorts during early growth, and (3) inter-generational stress memory, formed by stress-induced changes in the epigenome of the seedling.

Multivariate Analysis of Genetic Diversity in the Ethiopian Garden Cress (Lepidium sativum L.) Genotypes

Aims: The use of multivariate techniques is an important strategy for germplasm classification and study of genetic relationships among genotypes. This study was designed to evaluate using multivariate analysis the genetic divergence among 112 garden cress (Lepidium sativum L.) genotypes collected from different Administrative Zones of Ethiopia. Methodology: The experiment was conducted at Haramaya University Research Site and Kulumsa farmer field. Twelve agro-morphological traits were evaluated in Randomized Complete Block Design (RCBD) with two replications. Region-wise analyses of variance, principal component and cluster analyses were applied. Results: The analysis of diversity pattern based on the region of genotype origin revealed highly significant variability within and between regions of origin for almost all studied traits. The geographical pattern of distributions of genotypes in groups were not dependent on the regions of origin. The first three principal components explained 80.3% of the total variations suggesting that traits such as number of secondary branches, days to maturity, plant height, biomass/plant and biomass/plot, harvest index, grain yield/plant, thousand seed weight and grain yield/ha are the principal discriminatory traits in the germplasm studied. The cluster analysis categorised the 112 genotypes into six groups. The most diverse genotypes were found between cluster I and II which could be used for producing new genetic variability and exploitation of heterotic effects with the traits of interest in crossing programs. Conclusion: The genetic diversity existing in the current study could be utilised in the genetic improvement of the Ethiopian garden cress germplasm.

Environmentally smart animal agriculture and integrated advisory services ameliorate the negative effects of climate change on production

The objective is to discern how Charles Darwin’s Origin of species (1859) and the theory of natural selection and evolutionary biology – ‘a grain in the balance will determine which individual shall live and which shall die’– are core to achieving environmentally and climate-smart, economically viable, sustainable animal agriculture in a changing climate. Darwin’s ‘survival of the fittest’ theory implies inherent comparative advantage of survivors over the succumbed in any given environment. An animal’s phenotype (P) results from interaction of its genotype (G) and the environment (E), expressed as P = G x E. Human migration has transferred livestock breeds from places of origin to distant continents and agro-ecological zones, far from where they have inherent comparative production advantage. For example, crossbreeds of Bos taurus and Bos indicus have higher average performance than median of either parent population. However, the heterotic effect of hybrids is associated with loss of environmental adaptation compared with parent populations. Indigenous breeds, their phenotypes and ecotypes thrive best in distinct environments, ceteris paribus . An environment is the sum total of conditions that influence animal productivity in the habitat. These include nutrition, genetics, disease, exposure to parasites, management practices, climate, rainfall, humidity, heat and cold stressors, and advisory services. Hybrids lose some adaptive capacity compared with parents, and require habitat modifications if they are to express their fullest genetic potential. In the light of this and of global warming challenges to livestock production, it is scientifically and technically prudent to exploit the inherent comparative production advantages of indigenous genotypes, phenotype and ecotypes, when mitigating climate change, more so in low-input animal agriculture systems of sub-Saharan Africa and at similar locations. Climate change poses multidisciplinary challenges that require integrated collaborative cross-discipline research, extension and training to provide holistic solutions. Keywords: Climate-smart, genotype, livestock production efficiency, global warming, indigenous breeds, mitigation strategies

Potential of Malian Landraces in Hybrid Combination

The first possibility of economic hybrid seed production in sorghum has been discussed since the discovery of the genetic-cytoplasmic male-sterility. The greater advantage of hybrids to yields, compared to cultivars, has been demonstrated throughout the world. Hybrids made with local cultivars of Mali used as the male parents and were compared to their parents. Heterosis was observed in all stages of plant growth. Seedling vigour and seedling drought tolerance were emphatically better than the Malian parents. The frequency of landraces with fertility reactions was more frequent than those with maintainer reactions. Significant and positive heterotic effects were recorded for grain yield per panicle and the panicle yield components, seed number and seed weight. However, there was no scope for direct exploitation of the hybrids involving the ATx623 and Malian landrace parents. The typical Caudatum “turtle-back” seed shape was dominant in hybrid combinations with all Malian races. This seed shape renders the grain more difficult to dehull than local cultivars. The grain of hybrids made with guinea parents had a thick brown sub coat with astringent tannins, which was undesirable for food uses.

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The Ethiopian garden cress (Lepidium sativum L.) is an important crop extensively used as food and medicine. In this study, total seed storage proteins of 112 garden cress genotypes collected from diverse growing regions in Ethiopia were investigated to assess patterns of genetic diversity and relationships. Using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), a total of 1774 stable protein bands were identified through discontinuous electrophoresis. Of these, 1597 bands were polymorphic. A maximum of 20 protein sub-units in the range of 15 to 75 kDa were observed per genotype. The similarity coefficient among these genotypes ranged from 0.25 to 1.00 with an average genetic dissimilarity of 0.2754. On the basis of Ward Euclidian distance, the genotypes were grouped into five major clusters, the largest one comprised of 62 genotypes (Cluster III) followed by 26 genotypes in Cluster I. Cluster IV and V contained a total of 14 genotypes that were the most distantly related to other groups, and thus can be potentially used as parents for exploitation of heterotic effects in hybrid breeding programs. Our findings using SDS-PAGE profiles revealed no obvious association between geographic region of origin and germplasm clustering. However, the polymorphism and cluster analysis indicated that garden cress genotypes differed greatly in the composition of seed proteins. This shows that protein profiling could be used as a rapid and reliable method for genetic diversity studies. In order to fully explore the protein based genetic diversity in garden cress germplasm, techniques such as 2-D gel electrophoresis are recommended in future studies. &nbsp; Key words: Cluster analysis, dissimilarity index, garden cress, Lepidium sativum, protein polymorphism, protein profiling, sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), seed storage protein.

Development of Diagnostic SNP Markers To Monitor Hybridization Between Sika Deer (Cervus nippon) and Wapiti (Cervus elaphus).

Sika deer (Cervus Nippon) and wapiti (Cervus elaphus) are closely related species and their hybridization can result in significant allele-shift of their gene pool. Additive genetic effects and putative heterotic effects of their hybridization on growth performance could confer considerable economic advantage in deer farming. Here, we used double-digest restriction site-associated DNA sequencing technology (ddRAD-seq) and detected ∼320,000 genome-wide SNPs from 30 captive individuals: 7 sika deer, 6 wapiti and 17 F1 hybrids (reciprocal cross). By screening observed heterozygosity of each SNP across four taxonomic groups, we report for the first time a resource of 2,015 putative diagnostic SNP markers (species-specific SNPs for sika deer and wapiti), which can be used to design tools for assessing or monitoring the degree of hybridization between sika deer and wapiti. These ddRAD-seq data and SNP datasets are also valuable resources for genome-wide studies, including trait discovery for breeders of domestic deer.

Comparison of methods for the estimation of best parent heterosis among lines developed from interspecific sunflower germplasm

Pre-breeding and elite breeding are two steps in creating high yielding sunflower hybrids that differ in well established procedures and selection methods. However, a methodology that bridge efficient use of introgression lines as product of pre-breeding procedures and their crossing to elite inbreed lines, is not yet very well established. Therefore, the development of cost- and time-efficient methods for the determination of best parent heterosis and the use of best inbred lines in crosses with introgression lines for obtaining high-yielding and stable hybrids is highly desirable. In this regard, sixteen Cytoplasmic Male Sterile (CMS) inbred lines (A) derived from four heterogeneous interspecific lines originating from three annual: H. debilis silvestris (DEB-SIL), H. praecox runyoni (PRA-RUN), H. deserticola (DES) and one perennial H. resinosus (RES) wild species were evaluated. Seven agronomic traits were measured over a period of 2 years and 38 DNA loci were analysed, in order to compare four different methods for the estimation of best parent heterosis (BPH). New inbred lines were characterized by Principal Component Analysis (PCA) of morphological traits and Principal Coordinate Analysis (PCoA) of molecular marker data. Line × tester mating design was used to evaluate General Combining Ability (GCA), while Genetic Distance (GC) estimated by markers was evaluated as a predictor of BPH by Locally Weighted Sequential Smoothing (LOESS). Analysis of combining ability is one of the most important tools breeders use to identify superior inbred lines on the basis of their performance in hybrid combinations. Results obtained in this research show that PCA of morphological and PCoA of molecular marker data on parental lines are generally in agreement with GCA effects for examined traits. GD versus BPH relationships indicate that intermediate to high GD between parental lines was optimal for best heterotic effects of most traits. In this study, we show that the combination of the PCA of morphological data, PCoA of molecular marker data and GD between parental lines is fast and affordable, giving the most important information for parental choice of introgression and elite lines in sunflower breeding programs.

Assessment of Ratooning Ability and Heterotic Effects for Yield and Yield Contributing Traits in Intraspecific Hybrids of Upland Cotton

The development of high yielding cotton hybrids is essential to meet the current cotton demands. On the other hand, the cotton ratooning allows to obtain maximum seed yields with early maturity of plant. Therefore, the present study was aimed to investigate the per se performance, ratooning ability and heterosis effects for yield and yield contributing traits in 28 novel hybrids through line x tester analysis by considering four varieties as lines and seven varieties as testers. Significant variability was observed for all investigated traits excluding the number of monopodial branches and boll weight traits in parents and their 28 hybrids. Among the parents, TSH 0499 and TSH 04/115 exhibited a fair performance for yield and yield contributing traits and SURABHI, TSH 0250 and VS 9-S11-1 expressed superior ratooning ability. Therefore, these parents have a potential to be exploited for the development of the efficient cotton hybrids. Among the tested F1 hybrids, TSH 0499 x TCH 1777, BGDS 1063 x TCH 1819, TSH 0499 x TCH 1819 and TSH 04/115 x SVPR 4 hybrids recorded superior performance for number of bolls, boll weight, lint index and seed cotton yield in first crop, respectively. The hybrids ARBC 19 x TSH 0250, TSH 0499 x SURABHI , TSH 0499 x TSH 0250 and TSH 0499 x TCH 1705-101 displayed good ratooning performance for number of bolls, boll weight, lint index and seed cotton yield, respectively. All the hybrids expressed a range of significantly positive and negative heterosis for tested traits. However, the observed negative heterosis for seed index is desirable since the hybrids produce more lint. The results of this study would give insights into the understanding of genetic variance present in the intra-hirsutum hybrids.

Genetic Analysis for Yield and its Components in Bread Wheat

Eight bread wheat cultivars were used to study some earliness and yield and its component traits. The parental cultivars were employed to produce 28 F1 hybrids following 8 x 8 half Diallel crossing without reciprocals. The seeds of 28 F1 hybrids and their parents were planted to estimate mean squares due to parents and their crosses which were significant for all studied traits. The parental variety P3 was the best parent for earliness. However, P8 was the best for remained traits. The crosses (P1 x P4) and (P2 x P4) were the best combinations for earliness traits, while the six crosses were the best for remained traits. Highly significant negative desirable heterotic effects were detected for earliness, on the contrary for remained traits relative to mid and better parent. The mean squares associated with general and specific combining abilities detected significant and highly significant estimates for all studied traits. Results indicated that P4 (Sids12) was good combiner for earliness traits and most of yield and its component traits. The best cross combinations displayed fair amount of SCA effect were obtained from (P2 x P4) and (P4 x P5) for earliness traits, the six crosses for remained traits. The graphical analysis Wr/Vr indicated the importance of over dominance gene effects in controlling all traits. The results indicated the importance of additive and dominance genetic variances in controlling these traits. The a item was significant for most studied traits and more than b item. Narrow sense heritability was less than (0.50) for all traits except plant height trait (0.80). Positive alleles were not equally distributed among parents (H2/4H1 ≠ 0.25) for all studied traits. The magnitude of dominance (H1/H2) was significant or highly significant higher than additive components (D) for all traits, expect plant height trait. All estimates of environmental variance (E) were positive significant and highly significant for all studied traits indicating that all studied traits have greatly affected by environmental factors.

GENETIC BEHAVIOR OF YIELD AND FIBER TRAITS IN SOME BARBADENSE COTTON CROSSES

This investigation was carried out at Sakha Experimental Station, Agricultural Research Center during four seasons 2013, 2014, 2015 and 2016. Five populations (P1, P2, F1, F2 and F3) for the four barbadense cotton crosses namely (Uzbekstan1 x C.B 58), (TNB x C.B 58), (BBB x C.B 58) and (Giza 94 x Giza 45) were used in this investigation to study the genetic behaviour of yield and its components and fibre traits. The aim of the present investigation was to study heterosis, inbreeding depression and type of gene action in four intra-specific crosses to obtain additional information about some genetic parameters to help the breeder to select effective breeding methods. The results showed that the potence ratio estimates indicated overdominance for seed cotton and lint yield/plant, boll weight, lint percentage and number of bolls/plant, while the quality traits exhibited partial dominance. Highly significant positive heterotic effects relative to mid-parent and better parent were obtained for seed cotton yield, lint cotton yield and number of bolls/plant, while it was for lint percentage. The inbreeding depression effects were highly significant for the number of bolls/plant, seed cotton yield and lint cotton yield. Highly significant values of additive and dominance were found for seed cotton yield, lint cotton yield and number of bolls/plant. Dominance effects for Micronaire value and fibre length were of greater magnitude than additive effects. Highly significant epistasis values were found for additive x additive and dominance x dominance with complementary action with non-additive effect. High broad-sense heritability values were calculated for all studied traits, while narrow sense heritability values were of low values for seed cotton and lint cotton yield. on the other hand the fibre quality traits exhibited high values in three crosses as well as the heritabilities of regression

Heterosis in cucumber (Cucumis sativus L.)

Heterosis for quantitative characters in 39 cucumber genotypes (19 parents and 20 F1 s) were investigated at the farm of Department of Genetics and Plant Breeding in Bangabandhu Sheikh Mujibur Rahman Agricultural University during March-November, 2013. Analysis of variance revealed highly significant differences among the parents and hybrids for 19 characters studied. Considerable coefficient of variation were observed for branches per plant, flesh thickness, placental thickness, fruit length ,fruit width, male and female flowers per plant, leaf length, leaf breadth, vine length, fruits per plant , fruit yield per plant indicating the scope of selection for those characters. The characters like branches per plant, male and female flowers per plant, fruit length, fruit weight, fruits per plant, fruit yield per plant contributed the maximum variability towards divergence among cucumber genotypes. Heterosis study depicted that the crosses Sobujsathi × Baromashi, Sobujsathi × Khira, Himaloy × Khira, exhibited significant positive heterosis for 50 % female flowering; Himaloy × Baromashi, Baromashi× Greenking for fruit length; Baromashi × Hero, Yuvraj × Khira for single fruit weight. Where Sobujsathi × Baromashi, Shila× Khira , Modhumoti × Hero and Modhumoti × Khira exhibited significant positive heterosis and heterobeltiosis for yield per plant. The highest positive heterotic effect for no. of fruits per plant was observed in Modhumoti × Baromashi (20%). The highest heterobeltiosis effect was found in hybrid Himaloy × Yuvraj (24.5%) followed by Sobujsathi× Khira (11.2 %), Modhumoti × Baromashi (10.0 %). Four crosses exhibited significant positive better parent heterotic effect for this trait and the combination Sobujsathi × Baromashi had the maximum heterosis on yield (47.6%). The maximum heterobeltiosis effect was found in Shila × Khira (27.73 %) followed by Modhumoti × Hero (15.14%) and Modhumoti × Khira (10%) for fruit yield.Bangladesh J. Agril. Res. 42(4): 731-747, December 2017

Modeling heterotic effects in beef cattle using genome-wide SNP-marker genotypes.

An objective of commercial beef cattle crossbreeding programs is to simultaneously optimize use of additive (breed differences) and non-additive (heterosis) effects. A total of 6,794 multibreed and crossbred beef cattle with phenotype and Illumina BovineSNP50 genotype data were used to predict genomic heterosis for growth and carcass traits by applying two methods assumed to be linearly proportional to heterosis. The methods were as follows: 1) retained heterozygosity predicted from genomic breed fractions (HET1) and 2) deviation of adjusted crossbred phenotype from midparent value (HET2). Comparison of methods was based on prediction accuracy from cross-validation. Here, a mutually exclusive random sampling of all crossbred animals (n = 5,327) was performed to form five groups replicated five times with approximately 1,065 animals per group. In each run within a replicate, one group was assigned as a validation set, while the remaining four groups were combined to form the reference set. The phenotype of the animals in the validation set was assumed to be unknown; thus, it resulted in every animal having heterosis values that were predicted without using its own phenotype, allowing their adjusted phenotype to be used for validation. The same approach was used to test the impact of predicted heterosis on accuracy of genomic breeding values (GBV). The results showed positive heterotic effects for growth traits but not for carcass traits that reflect the importance of heterosis for growth traits in beef cattle. Heterosis predicted by HET1 method resulted in less variable estimates that were mostly within the range of estimates generated by HET2. Prediction accuracy was greater for HET2 (0.37-0.98) than HET1 (0.34-0.43). Proper consideration of heterosis in genomic evaluation models has debatable effects on accuracy of EBV predictions. However, opportunity exists for predicting heterosis, improving accuracy of genomic selection, and consequently optimizing crossbreeding programs in beef cattle.

Growth Characteristics of Sahiwal x Zebu F1 Crossbred Cattle in Uganda

This study assessed the growth of Sahiwal x Zebu crossbreds under low input production conditions in Uganda. Primary data consisted monthly live body weights of 64 Sahiwal first filial generation (F1) crossbred calves born between 2013 and 2015. The herd was on pasture; water provided ad lib and routine control of ticks and worms done. The minimum, average and maximum birth weights for the herd were 15.0, 23.2+7.0 and 40.0 kg with a 13% heterotic effect. Birth weight was significantly (P

Genetic Diversity among Soybean [Glycine max (L.) Merrill] Genotypes Based on Agro Morphological Characters under Rainfed Condition of Manipur

The experiment was carried out to study the extent of genetic diversity among the 75 genotypes of soybean under rainfed condition of Manipur by employing Mahalanobis D2 analysis based on 13 morphological characters. The 75 genotypes of soybean were grouped into nine clusters. Maximum numbers of genotypes were included in the Cluster I comprising 28 genotypes followed by Cluster II with 13 genotypes, Cluster IV with 12 genotypes, Clusters III and V with nine genotypes each and clusters VI, VII, VIII and IX with 1 genotype each. The value of intra-cluster distances ranged from 0.00 to 1181. The highest inter-cluster distance (8937) was observed between Clusters III and IX. The character plant height (34.13%) contributed the highest to the total divergence of the genotypes, followed by pods per plant (29.62%) and days to 80% maturity (14.59%). The highest cluster means values for yield and its component characters were observed in Cluster IX. On the basis of inter-cluster distance, cluster mean values, mean per se performance it is advisable to attempt crosses between genotypes from Clusters III and IX which may lead to obtaining higher heterotic effect and broad spectrum variability in the segregants.

Research Article Genetic diversity among accessions of Capsicum annuum L. through morphoagronomic characters

Genetic variability among pepper genotypes is essential in obtaining hybrid combinations with greater heterotic effect and in obtaining superior strains. This work’s goal was to evaluate the genetic diversity between accessions of Capsicum annuum L., indicating the selection of promising individuals for ornamental purposes. The experiment was carried out in at the Plant Biotechnology Laboratory of the Center of Agricultural Sciences, Federal University of Paraiba. The experiment was conducted in a completely randomized design with 16 treatments and eight replications. The plants were evaluated for 28 morphoagronomic traits. Data were submitted to analysis of variance and grouped according to Scott and Knott's test at 1% probability. The Tocher grouping was performed based on Mahalanobis distance and analysis of canonical variables were performed with graphical dispersion of the accessions. All variables were significant by the F test (p = 0.01) and presented high heritability and a CVg/CVe ratio higher than 1.0 for most traits, indicating genetic divergence between accessions. In keeping with the Scott-Knott's test (p = 0.01), the accessions were grouped into two to eight classes, varying according to the character. The of Tocher optimization method separated the accessions into five distinct groups. There is phenotypic divergence between the accessions of Capsicum annuum L. which can be used in ornamental peppers’ breeding programs. Only the number of stamens trait presented a heritability value (65.81%) lower than 70%. The characters that most contributed to divergence among the accessions were fresh fruit mass, stem diameter, widest fruit diameter and fruit weight. The accessions UFPB001, UFPB004, UFPB45, UFPB77.3, UFPB099, UFPB134, UFPB390 and Calypso are designated as potential accessions for ideal ornamental pepper plant with vigorous seedling, small port, large flowers and small fruits. Ornamental pepper accessions with larger anthers are indicated for selection, for facilitating the breeder’s work during flower emasculations for crossings.

Heterosis for important qualitative and quantitative characters of mungbean

Forty hybrids incurred from five high yielding genetically diverse lines and eight testers for appraise eleven important quantitative and qualitative traits of mungbean. Mid parent, better parent and standard parent heterotic effects were estimated. The highest standard heterosis is observed for number of cluster per plant. The highest mid parent, better parent and standard parent heterosis for number of cluster per plant viz., 182.66 per cent, 173.44 per cent 196.61 per cent respectively, for the hybrid EC 396120 x IPM 99125. The highest standard heterosis of 31.5 percent for seed protein content was recorded for the hybrid between EC 396126 and CO GG 930. Based on per se performance and standard heterosis, hybrids were identified for heterosis breeding. The crosses, PANT M 103 x COGG 930, EC 396120 x IPM 99 125, AGG 10091 x CO 7, PANT M 103 x MH 565, AGG 100 91 x IPM 99 125, EC 396120 x IPM 0214, PANT M 103 x CO 7 and EC 396120 x PUSA VISHAL exhibited significant per se and standard heterosis for single plant yield. So these crosses were considered as superior crosses and further utilized in the breeding programme.