Rice is critical for sustainable food and nutritional security; however, nominal micronutrient quantities in grains aggravate malnutrition in rice-eating poor populations. In this study, we evaluated genetic diversity in grain iron (Fe) and zinc (Zn) contents using trait-linked simple sequence repeat (SSR) markers in the representative subset of a large collection of local and exotic rice germplasm. Results demonstrated that aromatic fine grain accessions contained relatively higher Fe and Zn contents in brown rice (BR) than coarse grain accessions and a strong positive correlation between both mineral elements. Genotyping with 24 traitlinked SSR markers identified 21 polymorphic markers, among which 17 demonstrated higher gene diversity and polymorphism information content (PIC) values, strongly indicating that markers used in current research were moderate to highly informative for evaluating the genetic diversity. Population structure, principal coordinate and phylogenetic analyses classified studied rice accessions into two fine grain specific and one fine and coarse grain admixture subpopulations. Single marker analysis recognized four ZnBR and single FeBR significant marker-trait associations (MTAs) contributing 15.41-39.72% in total observed phenotypic variance. Furthermore, high grain Fe and Zn contents linked marker alleles from significant MTAs were also identified. Collectively, these results indicate a wide genetic diversity exist in grain Fe and Zn contents of studied rice accessions and reveal perspective for marker-assisted biofortification breeding.

R ice is one of the most important food commodities and provides major portion of daily calories requirement, especially in underdeveloped and developing countries (Fukagawa and Ziska, 2019). The world population is increasing at an exponential rate, demanding approximately 70% increase in food production to meet the food security targets by 2050 (Fróna et al., 2014). Water scarcity or drought is one of the biggest threats to food security worldwide and could reduce crop production by 50% (Budak et al., 2015). Therefore, management of drought stress is crucial for successfully achieving the desired production targets. About 77% of the total cultivated rice is conventionally transplanted globally Abstract | Rice is the staple food of more than 50% of the world's population, and water scarcity is threating its sustainable production. Dry seeded rice (DSR) technology has water and labour saving advantages over conventional transplanting culture, however, poor crop establishment due to reduced germination in variable field conditions greatly hampers its large-scale adaption. To address subordinate germination issues, we investigated the effects of five salicylic acid (SA) concentrations (0, 75, 150, 225 and 300 ppm) on polyethylene glycol (PEG) induced drought stress conditions (0, -0.2, -0.4, -0.6 and -0.8 MPa). Highly significant (p < 0.01) effects of drought, SA and their interactions were observed on seed germination. Interestingly, varying SA concentrations imparted more pronounced effects under higher osmotic stress levels. Day-wise germination data indicated that the SA treatments alleviated inhibitory effects of different osmotic stress levels after 2-4 days of stress applications. Under medium to high osmotic stress levels, mean germination time, germination index and seed vigour index (SVI) of SA primed seeds were better than non-primed seeds. Remarkably, SVI of all SA concentrations under -0.2 MPa osmotic stress was surprisingly improved as compared with control and other osmotic stress levels, indicating a 'drought-escape strategy' in rice seeds under low osmotic stress level. Overall, our results indicated that seed priming with 225 ppm SA concentration is ideal under all environments and should be recommended in DSR system to improve early crop establishment and sustainable production.

In the present study, genetic parameters, agro-morphologic stability and clustering pattern of twenty promising elite basmati rice (Oryza sativa L.) lines including three checks were investigated in advance generation. Triplicated randomized complete block design (RCBD) was used during three consecutive years from 2016 to 2018 and the data were subjected to combined ANOVA, correlation, principal component, GGE biplots in order to demonstrate the stability and performance of these advance Basmati lines. A highly significant and exploitable level of genetic variability was found existed among tested inbred lines. Higher broad sense heritability (%) was observed among tested genotypes which specifies higher proportion of phenotypic variation attributed by genetic values. Correlation matrix portrayed significantly positive relationship of grain yield with maturity days; significantly positive relationship of plant height with days to maturity and highly negative with panicle length and thousand grains weight. Dendrograms divided the genotypes into six distinct Clusters. Based on GGE biplots, PK10324-1-1 followed by PK9444-8-1-2 and PK10029-13-2-1 were identified to be most superior and potential candidate Basmati lines with better yield and stability across three years (growing seasons). Whereas, Super Basmati (check), PK 10436-2-1-1, PK10437-14-2-1 exhibited lowest yield stability across test environments. Test-environment analysis indicated that genotypes PK10324-1-1 and PK9444-8-1-2 were best suited for 2017 season, genotypes PK10967-30-1, Chenab Basmati and PK 10355-13-2-1 were best suited for 2018, genotypes PK9966-10-1 and PK 10434-6-2-1 were best suited for 2016 season, whereas genotype PK10029-13-2-1 performed equally well in 2017 and 2018. Principal Component Analysis (PCA) also displayed stability in performance relative to all studied traits in all the advance Basmati lines. Convincingly, the higher yielding and more stable among the studied advance Basmati lines can be utilized as new candidate Basmati lines as compared to existing Basmati verities used as checks.

Tribolium castaneum is one of the major stored grain pests causing infestation in both rice and wheat mills. Present study was designed to estimate the feeding preference and associated post-harvest losses (growth rate, grain damage and grain losses) of T. castaneum on four rice cultivars (Super Basmati, Basmati 515, Super Basmati 2019 and Super Gold) and their components (Paddy, Brown rice and Polished rice) under controlled conditions. Results indicated that maximum growth rate (64.00), grain damage (76.67%), and grain weight loss (5.15%) were recorded on polished rice of Basmati 515 as compared to other cultivars and their components. Tribolium castaneum preferably feeds on all the components of Basmati 515 as compared to the others. This study might be helpful for the rice millers and researchers for the timely appropriate management, development of new management tactics, and rice cultivars resistant to T. castaneum.Novelty Statement | This is the first study in Pakistan to test these four varieties (which are being grown on a large area in the Punjab) for feeding preference of T. castaneum and associated post-harvest losses.

Rice is critical for sustainable food and nutritional security; however, nominal micronutrient quantities in grains aggravate malnutrition in rice-eating poor populations. Here, we assessed genetic diversity in grain iron (Fe) and zinc (Zn) contents using trait-linked simple sequence repeat (SSR) markers in 56 fine and coarse grain rice accessions of different geographical origin. Aromatic fine gain accessions contained relatively higher Fe and Zn contents in brown rice (BR) than coarse grain accessions. Genotyping with 24 SSR markers identified 21 polymorphic markers, among which seventeen demonstrated higher gene diversity and polymorphism information content (PIC) values, strongly indicating that markers used in current research were moderate to highly informative for evaluating genetic diversity. Population structure, principal coordinate and phylogenetic analyses classified studied rice accessions into two fine grain specific and one fine and coarse grain admixture subpopulations. Single marker analysis recognized four ZnBR and single FeBR significant marker-trait associations (MTAs), contributing 15.41-39.72% in total observed phenotypic variance. Furthermore, high grain Fe and Zn contents linked marker alleles from significant MTAs were also identified. Collectively, these results indicate availability of wide genetic diversity in rice germplasm and perspective for marker-assisted biofortification breeding.