Diallel Cross Experiment Research Articles

Exploiting hybrid vigor to enhance survival and growth for whiteleg shrimp (Litopenaeus vannamei): A complete diallel cross experiment

Whiteleg shrimp (Litopenaeus vannamei) is an economically important cultured species that is extensively cultured in China. However, there is the potential for further optimization of its survival and growth traits that are key determinants of productivity in aquaculture. This study investigated the efficacy of hybridization, a genetic improvement technology leveraging hybrid vigor, as a strategy for enhancing these traits in L. vannamei. The study was conducted using a 4 × 4 complete diallel cross experiment involving four selected strains (5, 8, 9, and 10), with the aim of identifying potential crosses exhibiting hybrid vigor. The most suitable crosses were those between strains 8 and 9, where the mid-parent heterosis (H89) was 16.52% for survival and 18.93% for growth. Our findings revealed that most reciprocal hybrids displayed higher rates of survival than their inbred parents. Additionally, an age-dependent increase in the heterosis effect on weight was observed over mid-parents and single-parents in most hybrid offspring. These findings suggest that hybridization could be a promising approach to improving the survival and growth of whiteleg shrimp. Our crossing experiment has yielded novel genetic resources for shrimp breeding, ultimately enhancing the economic importance of whiteleg shrimp.

The cellulose–lignin balance mediated by auxin signal transduction affects the twisted growth of Yunnan pine trunk

Trunk twisting, a special phenomenon observed during plant growth, leads to remarkable changes in plant phenotypic plasticity and adaptability. However, it is a debate whether the trunk twisting belongs to environmental alteration or genetic variation. To understand the mechanisms underlying trunk twisting in Yunnan pine (Pinus yunnanensis Franch.), through a diallel cross experiment, we first determined that trunk twisting was controlled by recessive genes. Anatomical analysis identified that straight and twisty types differed significantly in xylem and phloem. RNA-seq of materials enriched by laser microdissection revealed several metabolic pathways with significant enrichment in twisty pines, including auxin signal transduction, photosynthetic carbon fixation and sucrose metabolism, etc. Application of exogenous auxin and auxin transport inhibitors (TIBA) can only change the growth rate, but cannot change the twisted or straight of the trunk. When auxin signaling inhibitors (auxinole) were added, the straight pines produce a tendency to twisty growth. Combined with enzyme activity assay and immunohistochemistry, we propose a working model. ARF can not only downregulate POR to block chlorophyll synthesis and photosynthesis but also upregulated Susy expression, and allows a large amount of sucrose to synthesize cellulose. Nevertheless, due to downregulated CBH expression and abnormal cellulolysis, cellulose accumulates and the lignin content decreases, eventually making the trunk highly prone to twisted growth. These results reveal the molecular mechanism of trunk twisting, and suggest that ARF expression method can be vital in trunk shape screening during the early growth stages of Yunnan pines.

Genetic analysis of freezing tolerance in camelina [Camelina sativa (L.) Crantz] by diallel cross of winter and spring biotypes.

Camelina biotypes had different responses to freezing stress, which was mainly inherited by additive gene effects and can be reliably used in breeding programs and for a better understanding of freezing tolerance mechanisms in camelina plants. Camelina [Camelina sativa (L.) Crantz] is a frost-tolerant oilseed plant that is cultivated as an autumn crop in semi-arid regions. However, camelina establishment in these areas is limited by low temperatures in winter that results in decreased seed yield. In the present study, genetic basis of freezing tolerance (FT) in spring and winter biotypes of camelina was analyzed at seedling stage using a diallel cross experiment. The parents consisted of two winter doubled haploid (DH) lines with high (DH34 and DH31), two spring lines with medium (DH19 and DH26), and two spring lines with low FT (DH08 and DH91). For this purpose, the parents along with F1 entries were subjected to freezing stress and survival percentage, electrolyte leakage, and lethal temperature for 50% mortality (LT50) of the lines were measured. Results showed that although both additive and non-additive effects of the genes determine the FT, further analyses indicated that it was mainly controlled by the additive effects. Therefore, selection-based methods may be more efficient for improving FT in camelina genotypes. The results of specific combining ability (SCA) and heterosis analysis among various DH lines suggested that more tolerant cultivars of camelina could be developed by targeted crossings. When a tolerant winter line and a susceptible spring line were crossed, their progenies showed a higher FT compared with the progenies of a cross between two susceptible spring lines indicating FT is controlled by additive effects of the genes in camelina plants. These findings provided new insight into the genetic basis of freezing-related traits in camelina and could be used for more sophisticated breeding programs.

Combining ability analysis on rhizomatousness via incomplete diallel crosses between perennial wild relative of rice and Asian cultivated rice

Compared with annual cultivated rice, perennial rice had great advantages of soil erosion control, labor saving, water and fertilizer management, etc. As the key organ for perenniality, rhizome can help grasses to achieve rapid expansion to occupy more environmental resources, and withstand the harsh environmental conditions. Oryza longistaminata, a perennial wild relative of rice with vigorous rhizomes, is an ideal donor for transferring perenniality to Asian cultivated rice (Oryza sativa). However, some hybrid F1 between O. longistaminata and cultivated rice didn’t have rhizomes. Obtaining rhizomatous hybrid progeny becomes a prerequisite for the rhizomes study. In this work, four varieties of O. sativa and three accessions of O. longistaminata were used to carry out an incomplete diallel cross experiment. It was found that most F1 hybrids had rhizomes with varying length and numbers. Data analysis showed that the general combining ability (GCA) of the female parents had significant effect on rhizome-related trait of the F1s. Nevertheless, the GCA of the male parents and special combining ability of the hybrid combination played minor effect. And we speculated that the appropriate choice for female parents is more crucial to obtain rhizomatous hybrid. As the first incomplete diallel cross between O. longistaminata and O. sativa, this work would be benefit to appropriate parent selection for genetic research and breeding of perennial rice.

APTITUD COMBINATORIA Y HETEROSIS EN VARIEDADES DE GERBERA (Gerbera × hybrida)

Crops that have a considerable number of cultivated varieties such as gerbera (Gerbera × hybrida) can be evaluated by diallel cross experiments for the formation of new hybrids. The aim of this research was to estimate the general combining ability (GCA) of six varieties of gerbera and the specific combining ability (SCA) of their diallel crosses and the heterosis on yield components and flower quality. The Griffing method 1 of parents and their direct and reciprocal F1 crosses was used with model II of random effects. The evaluation was carried out under a randomized complete blocks experimental design with four replications. The statistical analysis detected significant differences (P ≤ 0.01) within and between parents and crosses, as well as in the interactions, which showed wide variability between parents and significant maternal effects due to cytoplasmic inheritance. The greatest effects of GCA (P ≤ 0.01) for yield of floral stems were obtained by the IGL, MG2 and FAS progenitors, while the greatests effects of SCA were shown by crosses FAS × JES, ALC × IGL and DIN × IGL. Positive effects of heterosis for yield were found in the crosses FAS × IGL, JES × IGL, ALC × IGL, DIN × IGL, MG2 × IGL and FAS × MG2. The results suggest that Igloo and Fascination can be used as superior parents in breeding programs for the development of new gerbera varieties. Highly significant GCA values for flower yield indicate the relative importance of additive gene action over non-additive effects.

Dividing a Maternal Pie among Half-Sibs: Genetic Conflicts and the Control of Resource Allocation to Seeds in Maize.

Resource allocation to offspring is the battleground for various intrafamilial conflicts. Understanding these conflicts requires knowledge of how the different actors (mother, siblings with different paternal genotypes) influence resource allocation. In angiosperms, allocation of resources to seeds happens postfertilization, and the paternally inherited genome in offspring can therefore influence resource allocation. However, the precise mode of resource allocation-and, in particular, the occurrence of sibling rivalry-has rarely been investigated in plants. In this article, we develop a new method for analyzing the resource-allocation traits of the different actors (maternal sporophyte and half-sibs) using data obtained from a large-scale diallel cross experiment in maize involving mixed hand pollination and color markers to assess seed weight of known paternity. We found strong evidence for the occurrence of sibling rivalry: resources invested in an ear were allocated competitively, and offspring with different paternal genotypes aggressively competed for these resources, entailing a measurable direct cost to the mother. We also show how resource allocation can be described for each genotype by two maternal traits (source effect, average sink responsiveness) and two offspring traits (ability to attract maternal resources, competitive ability toward siblings). We will discuss how these findings help to understand how genetic conflicts shape resource-allocation traits in angiosperms.

Variance-balanced row–column designs involving diallel crosses incorporating specific combining abilities for comparing test lines with a control line

ABSTRACTIn this paper, the problem of comparing t test lines with a control line under a row–column setup in complete diallel cross experiment is investigated when specific combining ability (sca) effect is included in the model. Three classes of Mating-Environmental Row–Column (MERC) designs have been obtained which are variance balanced for estimating the contrasts pertaining to general combining ability (gca) effects free from sca effects.

Growth and survival of a diallel cross for five strains of climbing perch (Anabas testudineus Bloch, 1792) in Thailand

A complete diallel cross experiment was conducted with five strains of climbing perch (Anabas testudineus) representing three wild populations collected from main river basins in Thailand and two farm populations in southern Thailand. Growth performance was recorded from 794 individually tagged progeny of the 24 different strain combinations after a grow-out period of about 130 d in an earthen pond. Least squares means of body weight at harvest and absolute growth rates were computed for each strain combination. The Chumphon strain showed the highest growth performance (81.1 ± 1.1 g). The Surat Thani × Chumphon (the first strain represents the sire) showed the highest survival (65.4± 25.50%) among the purebreds and the crossbreds. The domesticated gene pool had much better growth in aquaculture than the wild gene pool. The correlation between the least squares means of body weight and the survival rates in the 24 strain combinations was 0.51 (p < 0.05). The mean heterosis of all crossbreds across traits was negative (−10.2± 22.7%). Heterosis appeared to decrease when different gene pools were crossed. This suggests that there may be outbreeding depression. The advantage of crossbred performance was clearly not shown in the study.

Multivariate Diallel Cross-Analyses for Body Weight of Rainbow Trout,Oncorhynchus mykiss, in China

Crossbreeding is a common technical approach for the development of new commercial fish strains characterized by high performance and a short generation time, for the Chinese market. Here, five strains – Bohai, Denmark, Donaldson, Norway, and California – of rainbow trout were used in a complete diallel cross, along with self-breeding within each strain, to estimate general combining ability; specific combining ability (SCA); and linebred, maternal, and reciprocal effects. These strains were defined based on their location of origin; the Bohai strain was domesticated and has been maintained since 1959 by the Bohai cold-water fish experimental station in China. Applying univariate and multivariate genetic analyses for body weight using the data set from this complete diallel cross experiment, we found that the cross combination with the Donaldson strain exhibited the most positive growth performance, whereas the Bohai ♀ × Donaldson ♂ cross was the highest performing cross combination in the experiment. Multiple significance tests showed that 40% (4 of 10) of the significant SCA based on univariate analyses (P 0.05). These results suggested that multivariate genetic analyses may provide more reliable reference guidelines for decision making by managers of breeding programs.

Assessment of immune-competence traits among native and cross bred chicken

A 3x3 diallel cross experiment between indigenous breeds [Ankleshwar (AN), Nicobari (NC)] and exotic breed (CARI Red) was carried out to study the immune-competence traits like humoral and cell mediated immune (CMI) response. A total of 540 birds were grouped into nine (three pure and six cross breeds, n=60/group) to conduct this 3 × 3 complete diallel cross experiment. Of which a total of 180 birds (n=20/group) were taken as representative birds as 10 male and 10 female from each genetic group to study the immuno-competence traits. Each bird was injected with 1 ml of 1% suspension of Sheep Red Blood Cells (SRBC) intravenously at 6th week of age to study the humoral immune response. The serum antibody titre against SRBC was measured by Heam agglutination (HA) test. After 10th week of age, the cell mediated immune response was assessed via intra-dermal injection of Phytohemagglutinin type P (PHA-P) on 3rd and 4th toe of the right foot of the chicken. The results of this study showed that there was significant difference (P<0.05) in humoral immune response between mating systems and genetic groups. The crossbreds showed significantly higher humoral and cell mediated immune response than purebreds. However, among purebreds, the CR showed better immune response. Moreover, the crosses of CR×NC showed higher humoral and Cell mediated immune response than others, followed by NC×CR. It is concluded that CARI Red as male and Nicobari as female showed better humoral and cell mediated immune response than others.

Optimal Block Designs for Diallel and Double Cross Experiments

ABSTRACT: Methods of construction of optimal block designs for a diallel cross and double cross experiments are proposed for even value of p of parental lines. The proposed designs are obtained by using unreduced balanced incomplete block designs.

Diallel cross analysis of plesiomorphic traits in Triticum aestivum L. genotypes

We conducted a 5 x 5 complete diallel cross experiment in bread wheat (Triticum aestivum) with the genotypes 6309, Chkwal-50, Dhrabi, Bhkhar-02, and FS-08. Our objective was to evaluate the type of gene action and the general and specific combining abilities required for various morphological traits in wheat. The results of analysis of variance revealed highly significant differences among genotypes for all the investigated traits. The results of joint regression analysis showed that the data for all the investigated traits fitted a simple additive dominance model. Graphical representation of variance and covariance suggested that most of the investigated traits were controlled by overdominance gene action. However, the peduncle length and plant height were controlled by additive gene action. Variety 6309 carried the highest number of dominant genes for the number of spikelets per spike, number of tillers per plant, plant height, number of fertile tillers per plant, and grain yield per plant. Chakwal-50 carried the highest number of recessive genes for grain yield per plant, number of tillers per plant, number of grains per spike, number of fertile tillers per plant, and plant height. Chakwal-50 and 6309 were the best general combiners for number of spikelets per spike, number of grains per spike, grain yield per plant, 1000-grain weight, number of fertile tillers per plant, and number of tillers per plant. On other hand, 6309 performed well in specific crosses with Chakwal-50, FS-08, and Bhakhar-02 for spike length and number of tillers per plant.

Diallel cross designs for test versus control comparisons

Block designs for diallel crosses for comparing a group of test lines with a control line are suitable when the experimenters are interested to estimate test vs. control comparisons with respect to their general combining ability effects with a smaller variance. In this paper, some families of small block designs for diallel cross experiments for test vs. control comparisons have been obtained. Out of these, some designs are suitable when the experimenter cannot have blocks of equal size while the others yield designs with equal block size. As the number of lines increases, the variance of estimated contrasts pertaining to test vs. test lines as well as test vs. control lines decreases. Moreover, test vs. control comparisons are made with less variance as compared to test vs. test comparisons, in all the cases.

Use of GGE biplot methodology for genetic analysis of yield and related traits in melon (Cucumis melo L.)

Dehghani, H., Feyzian, E., Jalali, M., Rezai, A. and Dane, F. 2012. Use of GGE biplot methodology for genetic analysis of yield and related traits in melon (Cucumis melo L.). Can. J. Plant Sci. 92 :7 7� 85. A complete diallel cross experiment of six local Iranian melon populations (Eyvanaki, Abasali, Tashkandi, Hose-sorkh, Mashhadi and Mirpanji) and one cultivar (Ananasi) was conducted. Fruit number, average weight per fruit, yield and acceptable yield were re-evaluated using GGE biplot methodology. The two principal components of biplot explained 70, 58, 86 and 88% of total observed variation for yield, acceptable yield, average weight per fruit and fruit number per plant, respectively. Mirpanji had the highest GCA for yield, acceptable yield and average weight per fruit, but the highest negative GCA for fruit number per plant. Abasali showed the highest positive GCA for fruit number. Biplot analysis allowed a rapid and effective overview of general combining ability (GCA) and specific combining ability (SCA) effects of the populations, their performance in crosses, as well as grouping patterns of similar genotypes.

Use of GGE biplot methodology for genetic analysis of yield and related traits in melon (Cucumis meloL.)

Dehghani, H., Feyzian, E., Jalali, M., Rezai, A. and Dane, F. 2012. Use of GGE biplot methodology for genetic analysis of yield and related traits in melon ( Cucumis melo L.). Can. J. Plant Sci. 92: 77–85. A complete diallel cross experiment of six local Iranian melon populations (Eyvanaki, Abasali, Tashkandi, Hose-sorkh, Mashhadi and Mirpanji) and one cultivar (Ananasi) was conducted. Fruit number, average weight per fruit, yield and acceptable yield were re-evaluated using GGE biplot methodology. The two principal components of biplot explained 70, 58, 86 and 88% of total observed variation for yield, acceptable yield, average weight per fruit and fruit number per plant, respectively. Mirpanji had the highest GCA for yield, acceptable yield and average weight per fruit, but the highest negative GCA for fruit number per plant. Abasali showed the highest positive GCA for fruit number. Biplot analysis allowed a rapid and effective overview of general combining ability (GCA) and specific combining ability (SCA) effects of the populations, their performance in crosses, as well as grouping patterns of similar genotypes.

Optimal block designs for CDC experiments method (2)

Incomplete block designs for a complete diallel cross (CDC) experiment known as method (2) of Griffing (1956) are proposed. These designs are derived by using mutually orthogonal Latin squares of order p, when p is a prime integer or power of a prime integer. With p inbred lines, the [p(p + 1)/2 − 1] degrees of freedom, for this method of Griffing, are partitioned into two orthogonal sets of (p − 1) and p(p − 1)/2 degrees of freedom the former for general combining ability (g c a) and the latter for specific combining ability (s c a) effects, respectively. These designs are optimal in the sense of Kempthorne (1956). The analysis includes the analysis of variance and the estimation of general combining ability and of specific combining ability. The analysis is illustrated numerically.

Genetic evaluation of a complete diallel cross involving three populations of freshwater prawn (Macrobrachium rosenbergii) from different geographical regions of India

Estimates of additive genetic, reciprocal and average heterosis effects were obtained from a three by three complete diallel cross experiment for giant freshwater prawn Macrobrachium rosenbergii. The data were generated in two batches. Three populations were sampled from the states of Gujarat (West), Kerala (South West) and Orissa (East) in India. The two mating batches of diallel crosses were combined in the analysis. A total 4773 animals (2233 in Batch 1 and 2540 in Batch 2) were tagged with VIA (Visible Implant Alpha numeric tags). A total of 2545 animals (979 and 1566 from Batch 1 and 2, respectively) were harvested with readable VIA tags and were; therefore available for analysis. The fixed effects included in the models were test environment (ponds 1 or 2 in batch 1, ponds 3 or 4 in batch 2), sex (male or female) and batch (1 or 2). Age at harvest was fitted as linear covariate. The genotype effect was partitioned into additive, non additive and reciprocal cross effects. Body weight, standard length and carapace length were recorded during tagging, sampling and harvesting. Estimates of additive genetic effect in the three stocks showed that the Kerala stock had greater body weight, carapace length and standard length, followed by Orissa then Gujarat. Average heterosis for body traits was low (3.1 to 6.3%) and not significantly different from zero. The results are discussed with respect to the choice of the most appropriate breeding strategy to improve the performance of M. rosenbergii in India.

Genetic dissection of yield and its components in upland cotton ( Gossypium hirsutum L.)

A 4x4 diallel cross experiment involving three exotic lines that is DPL-775, 71-821 Bulk-OP and Coker-100/A-2 and one local line that is MNH-53, was conducted for genetic analysis of yield and its components in upland cotton, to evaluate the gene action for different agronomic and fiber characters in upland cotton. Additive gene action with partial dominance appeared to control plant height, number of sympodial branches, number of bolls, yield of seed cotton, boll weight and lint percentage, where as over dominance type of gene action was noted for number of seeds per boll, seed index, lint index, staple length, fiber fineness. On over all basis 71-82 Bulk-OP has maximum dominant genes for number of sympodial branches, yield of seed cotton, seed index, lint index and fiber fineness while dominant genes for number of seeds per boll, boll weight, lint percentage and staple length are present in Coker-100/A-2. MNH-53 has maximum dominant genes for plant height and number of bolls while DPL-775 did not possess and dominant genes for any character. Key words: Gene action, diallel cross agronomic traits, cotton.

Optimal block designs for diallel crosses

Dey and Midha (Biometrika 83(2):484–489, 1996) constructed optimal block designs for complete diallel cross experiment using triangular partially balanced incomplete block designs with two associate classes. They listed optimal block designs for the lines in the range from 5 ≤ v ≤ 10. In this paper, we are also proposing additional optimal block designs for complete diallel cross experiment using two associate class partially balanced block designs for some additional values of v. Our method yields designs for proper and non-proper settings for complete diallel cross experiments. The proper and non proper designs are optimal in the sense of Kempthorne (Genetics 41:451–459, 1956) and non-proper designs are universally optimal in the sense of Kiefer (A survey of statistical design and linear models, North Holland, Amsterdam, 1975). The list of practically important designs is also given.

Genetic analysis for brix weight per stool and its component traits in sugarcane (Saccharum officinarum)

Brix weight per stool (BW) of sugarcane is a complex trait, which is the final product of a combination of many components. Diallel cross experiments were conducted during a period of two years for BW and its five component traits, including stalk diameter (SD), stalk length (SL), stalk number (SN), stalk weight (SW), and brix scale (BS) of sugarcane. Phenotypic data of all the six traits were analyzed by mixed linear model and their phenotype variances were portioned into additive (A), dominance (D), additive x environment interaction (AE) and dominance x environment interaction (DE) effects, and the correlations of A, D, AE and DE effects between BW and its components were estimated. Conditional analysis was employed to investigate the contribution of the components traits to the variances of A, D, AE and DE effects of BW. It was observed that the heritabilities of BW were significantly attributed to A, D and DE by 23.9%, 30.9% and 28.5%, respectively. The variance of A effect for BW was significantly affected by SL, SN and BS by 25.3%, 93.7% and 17.4%, respectively. The variances of D and DE effects for BW were also significantly influenced by all the five components by 5.1%(85.5%. These determinants might be helpful in sugarcane breeding and provide valuable information for multiple-trait improvement of BW.