Genetic studies of different agronomic, quality and yield contributing traits in Gossypium hirsutum L.

An experiment of 4 × 4 diallel was carried out to study the gene action of different yield and yield contributing traits of four advanced cotton cultivars using Mather and Jinks approach. Significant variation was present for all the characters (P< 0.01). The data on recorded parameters revealed that most of the traits were fully or partially fit for genetic interpretation. Additive gene action (D) was significant and pre-dominant for all the characters while seeds per locule showed dominance effect of H1& H2, and it was confirmed by the value of degree of dominance (H1/D 0.5). The value of H2/4H1 and h2 (measures the direction of dominance) demonstrated asymmetrical division of dominant genes for all traits, except ginning out turn (G.O.T) percentage and fiber length, in parental material. All the studied traits showed high value of narrow sense heritability (h2NS), however seeds per locule possessed low heritability. The genetic analysis revealed that all the characters could be improved by progeny and pedigree selection, whereas hybrid dynamism could be exploited in the trait like seeds per locule.

Role of conventional and molecular techniques in soybean yield and quality improvement: A critical review

The soybean is one of the most significant legume crops around the globe and serves as a source of dietary components for humans and animals. It has a higher percentage of protein compared to any other crop. Soybean yield and quality have been affected by many environmental factors. The genetic mechanism of yield and quality is still not clearly understood. Hence there is still a need to investigate the major potent factors to shed light on the mechanism behind yield and quality traits in soybean. Recently, a lot of significant work, including novel QTL, genes, and CRISPR-based genome editing in soybeans, has been done, which opened new doors of hope. The current review has presented detailed work done previously. We have also discussed the role of different breeding techniques in the conventional way of soybean improvement. The genetic factors regulating yield, quality, and disease resistance could be further cloned and transferred into elite cultivars to attain higher output in the current situation of changing environment. The integrated use of several techniques, like CRISPR/Cas9, next-generation sequencing, omics approaches, would be a fruitful way to improve soybean yield and quality. Besides this, hybridization, mass selection, pure line selection, backcross breeding, and pedigree selection should be adopted to develop novel soybean cultivars. This review concluded that soybean yield and quality improvement could be enhanced by exploring its genetic mechanism using several molecular and conventional methods.

Rice (Oryza sativa L.) breeding for novel black short grain associated with yield, cooking quality, high nutrition and antioxidant potential derived from indica black rice x japonica white rice

The combination of the trend of Japanese food consumption with the health benefits of black rice is in high demand for rice consumers in Thailand. For this challenge, incorporation of desirable traits from temperate japonica white rice, Akitakomachi and tropical indica black rice, Riceberry was performed by pedigree selection with maker assisted selection (MAS) and these desirable traits have been presented in breeding progenies. The three candidate lines showed highly favorable agronomic characteristics and a high grain yield, with short grains and good cooking quality, similar to japonica rice, in a tropical climate. In addition, these lines showed black coloration of the pericarp, indicating high nutritional value (including Fe, Zn, Vit B6, Vit E and folate levels) and phytochemical, antioxidant and antidiabetic activities, similar to those of the Riceberry parent. In terms of the sensory testing of unpolished rice, two breeding lines (69-1-1 and 72-4-3) showed higher scores than their parents. However, only 69-1-1 was identified as japonica type according to its genetic background. Therefore, this breeding program, involving the crossing of a temperate japonica white rice with a tropical indica black rice, can create novel black short grain rice variety adapted to a tropical environment, similar to japonica-type rice.

Estimation of Genetic Parameters for Body Weight and Some Colour Traits in the Seventh-generation Index Selected Nigeria Heavy Local Chicken Ecotype

Background: This study was conducted to estimate the genetic parameters of body weight and some colour traits in seventh generation (G7) index selected Nigerian Heavy Local Chicken Ecotype (NHLCE) progenies at point of lay to 12 weeks. Methods: 5 sires and 12 hens were used to generate the progenies used for the experiment. Traits measured included weekly body weight, egg colour, beak colour and feather colour. Data collected were subjected to one way analysis of variance in a Paternal half sib analysis using Animal model of SAS (2003). Four weeks body weight measurements, egg colour, beak colour and feather colour for 5 sires ranged from 1.29±0.05 1.54±0.07; 2.55±0.02 to 4.00±0.02; 2.45±0.02 to 4.83±0.02 and 1.73±0.02 to 4.58±0.04 respectively. Result: The new Duncan’s multiple range test shows that sire families are similar (p greater than 0.05) in the body weight and beak colour, but significantly differed (p greater than 0.05) in the egg colour and feather colour. The heritability estimates of mature body weight for week 3 was medium, while estimates of heritability for weekly mature body weight for weeks 1, 2 and 4, egg colour, beak colour and feather colour of NHLCE were low heritability. Low h2 of traits suggest that progeny and pedigree selection could be employed for improvement of the egg colour, beak colour and feather colour of NHLCE. The study showed positive genetic correlations between beak colour and egg colour, negative genetic correlations between beak and feather colour. This means that no decision can be taken in isolation as the selection of one trait will have consequences on other traits.

Development of High Yielding Cowpea [Vigna unguiculata (L.) Walp.] Lines with Improved Quality Seeds through Mutation and Pedigree Selection Methods

Cowpea [Vigna unguiculata (L.) Walp.] is a major legume crop and an important source of protein in Africa. The Kafr El-Sheikh University has a long history of cowpea breeding and improvement in Egypt. Two superior lines with high seed yield and quality were selected through mutation breeding and released to farmers as new varieties under the names Kafr El Sheikh-1 and Kaha-1. Crosses were made between these two varieties to further improve cowpea to meet farmers’ demand. Using the pedigree selection method, 13 new superior F10 lines were selected and evaluated over 2 years for seed yield and related traits, earliness, and protein content under low (16 plants/m2) and high (24 plants/m2) plant densities. The results showed that plants grown in narrower space produced significantly higher seed yield per unit area than the plants grown in wider space. All developed lines produced significantly higher seed yield than the two parental lines in the 2018 trial and Kaha-1 in the 2019 trial. Line number 6 proved to be the best genotype for earliness (73.5–73.9 days after sowing), seed yield (573–647 g/m2), and crude protein content (22.7–24.3%) in both trials. In addition, line 4 with bushy determinate growth habit and high seed quality was recently released as a new variety (Sakha-1). Several other cowpea lines have clear potential for release as new high-yielding varieties with early maturity and high seed quality for farmers in Egypt. Seeds of selected lines are available from Kafrelsheikh University. This shows that mutation breeding and pedigree selection methods are among the most promising breeding methods for cowpea improvement.

Resistance to Three Distinct Begomovirus Species in the Agronomical Superior Tropical Pumpkin Line AVPU1426 Developed at the World Vegetable Center

The Squash Leaf Curl China Virus (SLCCNV) and Tomato Leaf Curl New Delhi Virus (ToLCNDV) are species of Begomovirus (whitefly-vectored Geminiviridae) and cause serious damage to the cucurbit crops of the genus Cucurbita in the areas of South and Southeast Asia, across Asia, the Middle East and the Mediterranean, respectively. Cucurbita moschata’s inbred line AVPU1426, developed at the World Vegetable Center (WorldVeg) from a Bangladeshi landrace through pedigree selection, was observed to be resistant to both begomoviruses in field tests conducted at the WorldVeg Research and Training Station, Kasetsart University, Kamphaeng Saen, Thailand, which is a hotspot for these viruses. When AVPU1426 was tested for reaction to inoculation by viruliferous whiteflies with Squash Leaf Curl Philippines Virus (Taiwan strain) (SLCPV-TW) in the screen net-house at WorldVeg headquarters in Taiwan, it showed good resistance, though SLCPV-TW DNA-A could be detected in all inoculated plants, indicating that it did not show immunity to this virus. The objective of this study was to validate the resistance to SLCCNV and ToLCNDV in AVPU1426 by using whitefly-mediated inoculations to determine the mode of inheritance of the resistance. The results showed that AVPU1426 was resistant to SLCCNV and ToLCNDV. Upon crossing AVPU1426 with a susceptible check variety, Waltham Butternut, the resistance to both begomoviruses was observed to be conferred by a single recessive gene. This open-pollinated pumpkin line AVPU1426 bears flat round, mottled green immature fruits with yellow flesh in mature fruit. The fruit yield of AVPU1426 (20.74 t/ha−1) was comparable to ‘Rajah’ (18.61 t/ha−1), a recently released commercial F1 hybrid of East-West Seed (EWS). The fruit of AVPU1426 were estimated to have a good average β-carotene content (1.57 mg/100 g fresh weight). This line is a good source to breed pumpkins resistant to the three begomoviruses.

The long-term effects of genomic selection: Response to selection, additive genetic variance and genetic architecture

ABSTRACTGenomic selection has revolutionized genetic improvement in animals and plants, but little is known of its long term effects. Here we investigate the long-term effects of genomic selection on the change in the genetic architecture of traits over generations. We defined the genetic architecture as the subset, allele frequencies and statistical additive effects of causal loci. We simulated a livestock population under 50 generations of phenotypic, pedigree, or genomic selection for a single trait, controlled by either only additive, additive and dominance, or additive, dominance and epistatic effects. The simulated epistasis was based on yeast data. The observed change in genetic architecture over generations was similar for genomic and pedigree selection, and slightly smaller for phenotypic selection. Short-term response was highest with genomic selection, while long-term response was highest with phenotypic selection, especially when non-additive effects were present. This was mainly because the loss in genetic variance and in segregating loci was much greater with genomic selection. Compared to pedigree selection, genomic selection lost a similar amount of the genetic variance but maintained more segregating loci, which on average had lower minor allele frequencies. For all selection methods, the presence of epistasis limited the changes in allele frequency and the fixation of causal loci, and substantially changed the statistical additive effects over generations. Our results show that non-additive effects can have a substantial impact on the change in genetic architecture. Therefore, non-additive effects can substantially impact the accuracy and future genetic gain of genomic selection.

Genotyping crossing parents and family bulks can facilitate cost-efficient genomic prediction strategies in small-scale line breeding programs

Key message Genomic relationship matrices based on mid-parent and family bulk genotypes represent cost-efficient alternatives to full genomic prediction approaches with individually genotyped early generation selection candidates. Abstract The routine usage of genomic selection for improving line varieties has gained an increasing popularity in recent years. Harnessing the benefits of this approach can, however, be too costly for many small-scale breeding programs, as in most genomic breeding strategies several hundred or even thousands of lines have to be genotyped each year. The aim of this study was thus to compare a full genomic prediction strategy using individually genotyped selection candidates with genomic predictions based on genotypes obtained from pooled DNA of progeny families as well as genotypes inferred from crossing parents. A population of 722 wheat lines representing 63 families tested in more than 100 multi-environment trials during 2010–2019 was for this purpose employed to conduct an empirical study, which was supplemented by a simulation with genotypic data from further 3855 lines. A similar or higher prediction ability was achieved for grain yield, protein yield, and the protein content when using mid-parent or family bulk genotypes in comparison with pedigree selection in the empirical across family prediction scenario. The difference of these methods with a full genomic prediction strategy became furthermore marginal if pre-existing phenotypic data of the selection candidates was already available. Similar observations were made in the simulation, where the usage of individually genotyped lines or family bulks was generally preferable with smaller family sizes. The proposed methods can thus be regarded as alternatives to full genomic or pedigree selection strategies, especially when pedigree information is limited like in the exchange of germplasm between breeding programs.