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Heat stress is one of the major causes of low kernel yield of maize in Pakistan as compared to other countries like United State of America, Turkey, Canada, Argentina and China. To overcome this problem, the current study was designed to evaluate heat stress induced responses in maize hybrids for morpho-physiological and kernel quality related traits. The research was conducted at Maize and Millets Research Institute (MMRI), Yusafwala, Pakistan for three consecutive spring seasons (2017, 2018 and 2019). Maize hybrids were sown under two heat regimes: (i) normal sowing and (ii) sowing under heat stress (late sowing) for each spring seasons. Results revealed highly significant (P<0.05) differences among maize hybrids for kernel yield and related traits under both conditions and for all three seasons. Moreover, 11% to 36% reduction in kernel yield was observed during heat stress compared to normal sowing. Highest average percentage reduction was observed in local hybrid YH-5532 (28.7%) followed by all the three multinational hybrids NK-8711 (27.3%), P-1543 (23.4%) and DK-6724 (21.2%), respectively. This reduction in kernel yield was attributed to the reduction in thousand kernel weight (4.8% to17.2%), number of kernels per ear (4.7% to 13.3%), net photosynthetic rate (11% to 24.9%) and shelling percentage (up to 4.7%) as revealed by biplot analysis. Biplot analysis further unveiled that two local maize hybrids YH-5507 and YH-5427 were the most productive and heat tolerant hybrids under both conditions and for three consecutive seasons. Therefore, these hybrids are recommended general cultivation especially in heat prone areas. [ABSTRACT FROM AUTHOR]

Zn deficiency is one of the leading health problems in children and women of developing countries. Different interventions could be used to overcome malnutrition, but biofortification is most impactful, convenient, sustainable and acceptable intervention. Maize is one of the major crops grown and consumed in the regions with prevalent Zn malnutrition; therefore, this is suitable target for Zn biofortification. Zn biofortification of maize could be achieved through agronomic and genetic approaches. Discussion of agronomic approaches with genetic approaches is prerequisite because soils in developing countries are deficit of Zn and availability of Zn in soils is mandatory for estimating the genetic responses of maize genotypes through genetic approaches. Seed priming, foliar and soil applications are agronomic tools for biofortification, but solo and combined applications of these treatments have different effects on Zn enrichment. Genetic approaches include the increase of Zn bioavailability or increase of kernel Zn concentration. Zn bioavailability could be increased by reducing the anti‐nutritional factors or by increasing the bioavailability enhancers. Kernel Zn concentration could be improved through hybridization and selections, whereas genetically engineered attempts for improving Zn uptake from soil, loading in xylem, remobilization in grains and sequestration in endosperm can further improve the kernel Zn concentration. Key challenges associated with dissemination of Zn biofortified maize are also under discussion in this draft. Current review emphasized all of above‐mentioned contents to provide roadmap for the development of Zn biofortified maize genotypes to curb the global Zn malnutrition. [ABSTRACT FROM AUTHOR]

Abstract: Understanding of mungbean yellow mosaic disease resistance is crucial to develop resistant varieties to combat worldwide threat of the disease epidemics. This study was aimed to determine nature of disease resistance in terms of number of genes governing it and genetics of related traits. Experimental site was located on 31.43°N and 73.06°E with an elevation of 186 m, and evaluation trials were conducted during spring season due to high disease epidemics in this season. Two contrasting genotypes, that is, NM 6‐68‐2 (resistant) and NM 1‐32‐1 (highly susceptible), were crossed to raise six populations, that is, P1, P2, F1, F2, BC1 and BC2 for evaluation under protected and unprotected field conditions using chi‐square test and generation mean and variance analysis. It was discovered that disease resistance was governed by two major genes with additive effects. Disease resistance can easily be incorporated through backcrossing and direct selection following hybridization. Direct selection should be practised at earlier generation for plant height, chlorophyll contents and number of seeds per pod due to preponderance of additive effects whereas at later generations for seed yield per plant, 100 seed weight, harvest index, number of pods per plant and pod length due to involvement of duplicate epistasis. [ABSTRACT FROM AUTHOR]

Salinity is amongst the leading abiotic stresses which adversely affects the crop productivity. It brings multiple disorders in normal plant functionality and suppresses yield up to drastic level. Under subjection to salinity, maize crop interacts differently with different environmental conditions and shows different responses. Plants interact positively, negatively and sometimes no interaction with environment for various plant traits. Genotype × Environment Interaction (GEI) of maize genotypes with three salinity levels was studied for some selected morpho-physiological traits i.e. root shoot ratio, cholorphyll a, cholorphyll b, β-carotenoids, ascorbic acid, root density and leaf temperature using AMMI biplot analysis. OH41, OH28, OH8, USSR40 and WM13RA for root shoot ratio (RSR) and A556 for β-carotenoids (BCart) were proved stable genotypes whereas; all other genotype interacted with stressed conditions either positively or negatively. Ascorbic acid and β-carotenoid contents were proved good indicators of salt tolerance in maize plant. AMMI biplot analysis proved to be an effective technique for study of GEI. Stable genotypes can be regarded for further breeding program. [ABSTRACT FROM AUTHOR]

Saline soils are the source of severe abiotic stress, which hinders crop productivity. To compete the challenges of food security for rapidly growing population of the world, it is necessary to utilize marginal lands for cultivation by developing saline adapted varieties. Total six elite maize lines were used as parents following diallel mating design. Resultantly 30 Fjs were generated. Data were recorded for different adaptability indicators under saline environments in maize. Differences among mean squares for general combining ability (GcA), specific combining ability (ScA) and reciprocal effects for all the indicators were highly significant. Root length, shoot length, Na+ and K+ ion contents were governed by non-additive type of gene action whereas; leaf area was controlled by additive gene action. Under different saline environments, better adaptability level regarding GCA, SCA and their reciprocal effects were indicated in maize genotypes L7-2, OH-41 and WFTMS. The cross Q67 × L7-2 exhibited comparatively highest level of adaptability regarding SCA effects under saline environments. For reciprocal effects maize genotypes L7-2, Q67, OH-41 and WFTMS could be used in different crossing combinations for the development of maize hybrids adapted to different saline environments. © 2015 Friends Science Publishers [ABSTRACT FROM AUTHOR]

A complete 6 x 6 diallel mating design was followed to assess the genetic components for different traits in maize (Zea mays L.). Parents and F1 generations were sown in RCBD with three replications in the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad, Pakistan during 2012. The data regarding plant height, leaf area, number of kernels per ear, stomatal size, stomatal frequency, leaf venation and 100-grain weight in maize were recorded at maturity to assess the genetic components and combining abilities. Analysis of variance was done to assess the significance of genetic differences among genotypes. Graphical approach used for diallel studies showed that most of the traits studied were under control of additive gene action. Plant height, leaf area, stomatal frequency and stomatal size were found under control of non-additive gene action. Whereas ear diameter, ear length, number of kernels per ear, number of kernels per row, leaf venation and 100-grain weight were under control of additive gene action. [ABSTRACT FROM AUTHOR]

A hydroponic study was carried out to determine the response of 13 cotton (Gossypium hirsutum L.) genotypes at three salinity levels viz, 0.8, 8 and 16 dS m-1 for various physiological and biochemical traits. Data were subjected to metroglyph analyses for the estimation of genetic diversity under contrasting salinity regimes. The genotypes were grouped into five clusters with maximum index score of 97 per cluster. Minimum index score of 13 in case of cluster-V under non saline regime was observed. Three clusters were constructed with range of index scores from 119 to 23 at 8 dS m-1, while all genotypes were grouped into five clusters with maximum and minimum index scores 114 and 23 in cluster-I and cluster-IV, respectively at 16 dS m-1. Relative salinity tolerance was also observed among genotypes at two saline regimes. NIAB-111 and Russian (RL) were the most susceptible and SLH-41 and UCD-581 were found the most tolerant at 8 dS m-1, whereas at 16 dS m-1 NIAB-111 and MS-39 were proved most susceptible and Groog-25, FH-982, TX-DOS-5-76C and Russian okra (RL) as most tolerant. We conclude that genotypes belonging to different clusters show diversity in salinity tolerance and can be used for further breeding programs with focus on development of salinity tolerant germplasm on the basis of easily detectable physiological and biochemical criteria. [ABSTRACT FROM AUTHOR]