Meta-analysis of the quantitative trait loci associated with agronomic traits, fertility restoration, disease resistance, and seed quality traits in pigeonpea (Cajanus cajan L.).

A meta-analysis of quantitative trait loci (QTLs), associated with agronomic traits, fertility restoration, disease resistance, and seed quality traits was conducted for the first time in pigeonpea (Cajanus cajan L.). Data on 498 QTLs was collected from 9 linkage mapping studies (involving 21 biparental populations). Of these 498, 203 QTLs were projected onto "PigeonPea_ConsensusMap_2022," saturated with 10,522 markers, which resulted in the prediction of 34 meta-QTLs (MQTLs). The average confidence interval (CI) of these MQTLs (2.54 cM) was 3.37 times lower than the CI of the initial QTLs (8.56 cM). Of the 34 MQTLs, 12 high-confidence MQTLs with CI (≤5 cM) and a greater number of initial QTLs (≥5) were utilized to extract 2255 gene models, of which 105 were believed to be associated with different traits under study. Furthermore, eight of these MQTLs were observed to overlap with several marker-trait associations or significant SNPs identified in previous genome-wide association studies. Furthermore, synteny and ortho-MQTL analyses among pigeonpea and four related legumes crops, such as chickpea, pea, cowpea, and French bean, led to the identification of 117 orthologous genes from 20 MQTL regions. Markers associated with MQTLs can be employed for MQTL-assisted breeding as well as to improve the prediction accuracy of genomic selection in pigeonpea. Additionally, MQTLs may be subjected to fine mapping, and some of the promising candidate genes may serve as potential targets for positional cloning and functional analysis to elucidate the molecular mechanisms underlying the target traits.

Genome-wide association analysis to delineate high-quality SNPs for seed micronutrient density in chickpea (Cicer arietinum L.).

Chickpea is the most important nutrient-rich grain legume crop in the world. A diverse core set of 147 chickpea genotypes was genotyped with a Axiom(®)50K CicerSNP array and trait phenotyped in two different environments for four seed micronutrients (Zn, Cu, Fe and Mn). The trait data and high-throughput 50K SNP genotypic data were used for the genome-wide association study (GWAS). The study led to the discovery of genes/QTLs for seed Zn, Cu, Fe and Mn, concentrations in chickpea. The analysis of seed micronutrient data revealed significant differences for all four micronutrient concentrations (P ≤ 0.05). The mean concentrations of seed Zn, Cu, Fe and Mn pooled over the 2 years were 45.9 ppm, 63.8 ppm 146.1 ppm, and 27.0 ppm, respectively. The analysis of results led to the identification of 35 SNPs significantly associated with seed Zn, Cu, Fe and Mn concentrations. Among these 35 marker-trait associations (MTAs), 5 were stable (consistently identified in different environments), 6 were major (explaining more than 15% of the phenotypic variation for an individual trait) and 3 were both major and stable MTAs. A set of 6 MTAs, MTAs (3 for Mn, 2 for Fe, and 1 for Cu) reported by us during the present study have been also reported in the same/almost same genomic regions in earlier studies and therefore declared as validated MTAs. The stable, major and validated MTAs identified during the present study will prove useful in future chickpea molecular breeding programs aimed at enhancing the seed nutrient density of chickpea.

Mistletoe Eradicator - A Novel Tool for Simultaneous Mechanical and Chemical Control of Mistletoe.

Some species of mistletoes, an aerial plant hemiparasites, play a Janus-like role in ecosystems by being rich biodiversity hotspots due to their trophic and topic associations with various organisms and at the same time acting as biological pirates, exhausting the host trees by stealing water and nutrients via the haustorium. Many crop and timber trees are attacked by mistletoes, for example, dwarf mistletoes parasitize conifers, representatives of genus Tapinanthus target guava, and Phoradendron mistletoe target pecans. Recently, an increasing infestation of the European mistletoe (Viscum album subsp. album L.) in monoculture stands of common walnuts (Juglans regia L.) was recorded for the first time during 2018 in different regions of Kashmir Valley, India. The common chemical approach based on the spraying of mistletoe exophytes with the growth regulators, ethephon and glyphosate, was not efficient since V. album resprouted in the next vegetation season. Hand pruning of mistletoe was time-consuming, and a polyethylene covering resulted in the localized rotting of host tissues. The most efficient approach to eradicate mistletoe was the use of a novel tool called Mistletoe Eradicator, which allows to use mechanical and chemical means of mistletoe control simultaneously. It consists of a manipulating pole with the terminal pruning saw having a container filled with the growth regulator, from which the liquid slowly drops onto the saw blade through the nozzle. It allows working both from the ground and in the tree canopy. After the targeted application of 5%-10% ethephon or glyphosate to the base of the just pruned V. album stems (stubs), exophyte resprouting was significantly reduced 9 months after the pruning as compared to the only pruned or sprayed exophytes. An alternative variant of Mistletoe Eradicator was constructed in Ukraine filled just with a food color additive to track the liquid dropping and was successfully tested.