Color, antioxidant and nutritional composition of dehydrated country bean (Lablab purpureus) seeds using solar drying techniques and pretreatments in Bangladesh.

The country bean (Lablab purpureus), is a significant contributor of dietary protein and other essential components in human nutrition. Because of its elevated moisture content, it is susceptible to rapid decay, leading to losses after harvesting. The utilization of solar drying has attracted significant attention as a tactic to minimize nutrient depletion in dried goods and enhance their longevity. This study employed four solar drying techniques, namely long chimney, short chimney, box solar drying and open sun drying, along with pretreatments such as potassium metabisulfite, potassium-sodium tartrate, citric acid and ascorbic acid. The objective was to determine an effective solar drying method, combined with pretreatment, that can maintain the color and nutritional qualities of dried country bean seeds. The treatment combinations were organized in a factorial randomized complete block design (RCBD) with three replications. The data were subjected to a two-way analysis of variance (ANOVA) and a Duncan Multiple Range Test (DMRT) was conducted at a significance level of 5 % (p < 0.05). Results revealed that box solar dryer having the highest drying efficiency, retained the highest ß-carotene (82.94 %), vitamin C (90.15 %), protein (96.48 %), fat (11.63 %), and ash (90.50 %) with maximum DPPH radical scavenging activity (lowest IC50 209.49 µg/ml) compared to other driers. Besides, country bean seeds have noteworthy proximate compositions, antioxidant activity, and bioactive components treated with 1 % potassium metabisulfite. Furthermore, the country bean seeds dehydrated in box solar dryer after 1 % potassium metabisulfite treatment received the highest acceptance score on the five-point Hedonic scale (4.83-4.89 out of 5.00) and color appearance and the similar trend was further supported by principal component analysis. Thus, it can be inferred that using a box solar dryer with a 1 % potassium metabisulfite pretreatment is a feasible method for preserving the color and nutritional value of country bean seeds and reducing postharvest losses.

Genome-wide association studies of salinity tolerance in local aman rice.

The present study aimed to identify and characterize new sources of salt tolerance among 94 rice varieties from varied geographic origins. The genotypes were divided into five groups based on their morphological characteristics at both vegetative and reproductive stages using salinity scores from the Standard Evaluation System (SES). The experiment was designed as per CRD (Completely Randomized Design) with 2 sets of salinity treatments for 8 dS/meter and 12 dS/meter, respectively compared with one non-salinized control set. Using a Soil Plant Analysis Development (SPAD) meter, assessments of the apparent chlorophyll content (greenness) of the genotypes were done to comprehend the mechanism underlying their salt tolerance.  To evaluate molecular genetic diversity, a panel of 1 K RiCA SNP markers was employed. Utilizing TASSEL 5.0 software, 598 filtered SNPs were used for molecular analysis. Whole-genome association studies (GWAS) were also used to investigate panicle number per plant (pn, tiller number per plant (till), SPAD value (spad), sterility (percent) (str), plant height (ph) and panicle length (pl. It is noteworthy that these characteristics oversee conveying the visible signs of salt damage in rice. Based on genotype data, diversity analysis divided the germplasm groups into four distinct clusters (I, II, III and IV). For the traits studied, thirteen significant marker-trait associations were discovered. According to the phenotypic screening, seven germplasm genotypes namely Koijuri, Asha, Kajal, Kaliboro, Hanumanjata, Akundi and Dular, are highly tolerant to salinity stress. The greenness of these genotypes was found to be more stable over time, indicating that these genotypes are more resistant to stress. Regarding their tolerance levels, the GWAS analysis produced comparable results, supporting that salinity-tolerant genotypes having minor alleles in significant SNP positions showed more greenness during the stress period. The Manhattan plot demonstrated that at the designated significant SNP position, the highly tolerant genotypes shared common alleles. These genotypes could therefore be seen as important genomic resources for accelerating the development and release of rice varieties that are tolerant to salinity.

The Kernel Size-Related Quantitative Trait Locus qKW9 Encodes a Pentatricopeptide Repeat Protein That Aaffects Photosynthesis and Grain Filling.

In maize (Zea mays), kernel weight is an important component of yield that has been selected during domestication. Many genes associated with kernel weight have been identified through mutant analysis. Most are involved in the biogenesis and functional maintenance of organelles or other fundamental cellular activities. However, few quantitative trait loci (QTLs) underlying quantitative variation in kernel weight have been cloned. Here, we characterize a QTL, qKW9, associated with maize kernel weight. This QTL encodes a DYW motif pentatricopeptide repeat protein involved in C-to-U editing of ndhB, a subunit of the chloroplast NADH dehydrogenase-like complex. In a null qkw9 background, C-to-U editing of ndhB was abolished, and photosynthesis was reduced, resulting in less maternal photosynthate available for grain filling. Characterization of qKW9 highlights the importance of optimizing photosynthesis for maize grain yield production.

The Conserved and Unique Genetic Architecture of Kernel Size and Weight in Maize and Rice.

Maize (Zea mays) is a major staple crop. Maize kernel size and weight are important contributors to its yield. Here, we measured kernel length, kernel width, kernel thickness, hundred kernel weight, and kernel test weight in 10 recombinant inbred line populations and dissected their genetic architecture using three statistical models. In total, 729 quantitative trait loci (QTLs) were identified, many of which were identified in all three models, including 22 major QTLs that each can explain more than 10% of phenotypic variation. To provide candidate genes for these QTLs, we identified 30 maize genes that are orthologs of 18 rice (Oryza sativa) genes reported to affect rice seed size or weight. Interestingly, 24 of these 30 genes are located in the identified QTLs or within 1 Mb of the significant single-nucleotide polymorphisms. We further confirmed the effects of five genes on maize kernel size/weight in an independent association mapping panel with 540 lines by candidate gene association analysis. Lastly, the function of ZmINCW1, a homolog of rice GRAIN INCOMPLETE FILLING1 that affects seed size and weight, was characterized in detail. ZmINCW1 is close to QTL peaks for kernel size/weight (less than 1 Mb) and contains significant single-nucleotide polymorphisms affecting kernel size/weight in the association panel. Overexpression of this gene can rescue the reduced weight of the Arabidopsis (Arabidopsis thaliana) homozygous mutant line in the AtcwINV2 gene (Arabidopsis ortholog of ZmINCW1). These results indicate that the molecular mechanisms affecting seed development are conserved in maize, rice, and possibly Arabidopsis.

Multi-environment QTL analysis of grain morphology traits and fine mapping of a kernel-width QTL in Zheng58 × SK maize population.

KEY MESSAGE: Sixteen major QTLs regulating maize kernel traits were mapped in multiple environments and one of them, qKW - 9.2 , was restricted to 630 Kb, harboring 28 putative gene models. To elucidate the genetic basis of kernel traits, a quantitative trait locus (QTL) analysis was conducted in a maize recombinant inbred line population derived from a cross between two diverse parents Zheng58 and SK, evaluated across eight environments. Construction of a high-density linkage map was based on 13,703 single-nucleotide polymorphism markers, covering 1860.9 cM of the whole genome. In total, 18, 26, 23, and 19 QTLs for kernel length, width, thickness, and 100-kernel weight, respectively, were detected on the basis of a single-environment analysis, and each QTL explained 3.2-23.7 % of the phenotypic variance. Sixteen major QTLs, which could explain greater than 10 % of the phenotypic variation, were mapped in multiple environments, implying that kernel traits might be controlled by many minor and multiple major QTLs. The major QTL qKW-9.2 with physical confidence interval of 1.68 Mbp, affecting kernel width, was then selected for fine mapping using heterogeneous inbred families. At final, the location of the underlying gene was narrowed down to 630 Kb, harboring 28 putative candidate-gene models. This information will enhance molecular breeding for kernel traits and simultaneously assist the gene cloning underlying this QTL, helping to reveal the genetic basis of kernel development in maize.

Genome-wide dissection of the maize ear genetic architecture using multiple populations.

Improvement of grain yield is an essential long-term goal of maize (Zea mays) breeding to meet continual and increasing food demands worldwide, but the genetic basis remains unclear. We used 10 different recombination inbred line (RIL) populations genotyped with high-density markers and phenotyped in multiple environments to dissect the genetic architecture of maize ear traits. Three methods were used to map the quantitative trait loci (QTLs) affecting ear traits. We found 17-34 minor- or moderate-effect loci that influence ear traits, with little epistasis and environmental interactions, totally accounting for 55.4-82% of the phenotypic variation. Four novel QTLs were validated and fine mapped using candidate gene association analysis, expression QTL analysis and heterogeneous inbred family validation. The combination of multiple different populations is a flexible and manageable way to collaboratively integrate widely available genetic resources, thereby boosting the statistical power of QTL discovery for important traits in agricultural crops, ultimately facilitating breeding programs.