Virus Diseases of Peanut

Rising temperatures and drought stress limit the growth and production potential of lentil (Lens culinaris Medikus), particularly during reproductive growth and seed filling. The present study aimed to (i) investigate the individual and combined effects of heat and drought stress during seed filling, (ii) determine the response of lentil genotypes with contrasting heat and drought sensitivity, and (iii) assess any cross tolerance in contrasting genotypes. For this purpose, eight lentil genotypes (two drought-tolerant, two drought-sensitive, two heat-tolerant, two heat-sensitive) were either sown at the normal time (second week of November 2014), when the temperatures at the time of seed filling were below 30/20°C (day/night), or sown late (second week of February 2015) to impose heat stress (temperatures > 30/20°C (day/night) during reproducive growth and seed filling. Half of the pots in each sowing environment were fully watered throughout (100% field capacity) while the others had water withheld (50% of field capacity) from the start of seed filling to maturity. Both heat and drought, individually or in combination, damaged cell membranes, photosynthetic traits and water relations; the effects were more severe with the combined stress. RuBisCo and stomatal conductance increased with heat stress but decreased with drought and the combined stress. Leaf and seed sucrose decreased with each stress in conjunction with its biosynthetic enzyme, while its (sucrose) hydrolysis increased under heat and drought stress, but was inhibited due to combination of stresses. Starch increased under heat stress in leaves but decreased in seeds, but drastically declined in seeds under drought alone or in combination with heat stress. At the same time, starch hydrolysis in leaves and seeds increased resulting in an accumulation of reducing sugars. Heat stress inhibited yield traits (seed number and seed weight per plant) more than drought stress, while drought stress reduced individual seed weights more than heat stress. The combined stress severely inhibited yield traits with less effect on the drought- and heat-tolerant genotypes. Drought stress inhibited the biochemical processes of seed filling more than heat stress, and the combined stress had a highly detrimental effect. A partial cross tolerance was noticed in drought and heat-tolerant lentil genotypes against the two stresses.

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Effects of Drought, Heat and Their Interaction on the Growth, Yield and Photosynthetic Function of Lentil (Lens culinaris Medikus) Genotypes Varying in Heat and Drought Sensitivity.

The rising temperatures are resulting in heat stress for various agricultural crops to limit their growth, metabolism, and leading to significant loss of yield potential worldwide. Heat stress adversely affects normal plant growth and development depending on the sensitivity of each crop species. Each crop species has its own range of temperature maxima and minima at different developmental stages beyond which all these processes get inhibited. The reproductive stage is on the whole more sensitive to heat stress, resulting in impaired fertilization to cause abortion of flowers. During seed filling, heat stress retards seed growth by affecting all the biochemical events to reduce seed size. Unfavorable temperature may significantly affect photosynthesis, respiration, water balance, and membrane stability of leaves. To combat heat stress, plants acquire various defense mechanisms for their survival such as maintaining membrane stability, and scavenging reactive oxygen species by generating antioxida...

Food crops face rising temperatures: An overview of responses, adaptive mechanisms, and approaches to improve heat tolerance

1 * Abstract: The rising temperatures are resulting in heat stress for various agricul- tural crops to limit their growth, metabolism, and leading to significant loss of yield potential worldwide. Heat stress adversely affects normal plant growth and develop- ment depending on the sensitivity of each crop species. Each crop species has its own range of temperature maxima and minima at different developmental stages beyond which all these processes get inhibited. The reproductive stage is on the whole more sensitive to heat stress, resulting in impaired fertilization to cause abortion of flowers. During seed filling, heat stress retards seed growth by affecting all the biochemical events to reduce seed size. Unfavorable temperature may significantly affect photo- synthesis, respiration, water balance, and membrane stability of leaves. To combat heat stress, plants acquire various defense mechanisms for their survival such as maintaining membrane stability, and scavenging reactive oxygen species by generat- ing antioxidants and stress proteins. Thermo-tolerance can be improved by the accu- mulation of various compounds of low molecular mass known as thermo-protectants as well as phyto-hormones. Exogenous application of these molecules has benefited plants growing under heat stress. Alternatively, transgenic plants over-expressing the enzymes catalyzing the synthesis of these molecules may be raised to increase their endogenous levels to improve heat tolerance. In recent times, various transgen- ics have been developed with improved thermo-tolerance having potential benefits for inducing heat tolerance in food crops. Updated information about of the effects of heat stress on various food crops and their responses as well as adaptive mecha- nisms is reviewed here.

SOIL & CROP SCIENCES | REVIEW ARTICLE Food crops face rising temperatures: An overview of responses, adaptive mechanisms, and approaches to improve heat tolerance

Mungbean [Vigna radiata (L.) R. Wilczek var. radiata] is an important food and cash legume crop in Asia. Development of short duration varieties has paved the way for the expansion of mungbean into other regions such as Sub-Saharan Africa and South America. Mungbean productivity is constrained by biotic and abiotic factors. Bruchids, whitefly, thrips, stem fly, aphids, and pod borers are the major insect-pests. The major diseases of mungbean are yellow mosaic, anthracnose, powdery mildew, Cercospora leaf spot, halo blight, bacterial leaf spot, and tan spot. Key abiotic stresses affecting mungbean production are drought, waterlogging, salinity, and heat stress. Mungbean breeding has been critical in developing varieties with resistance to biotic and abiotic factors, but there are many constraints still to address that include the precise and accurate identification of resistance source(s) for some of the traits and the traits conferred by multi genes. Latest technologies in phenotyping, genomics, proteomics, and metabolomics could be of great help to understand insect/pathogen-plant, plant-environment interactions and the key components responsible for resistance to biotic and abiotic stresses. This review discusses current biotic and abiotic constraints in mungbean production and the challenges in genetic improvement.

Biotic and abiotic constraints in mungbean production-progress in genetic improvement.

Mungbean Yellow Mosaic India Virus (MYMIV) belonging to the genus begomovirus causes the yellow mosaic disease in a number of economically important edible grain legumes including mungbean (Vigna radiata), urdbean (Vigna mungo) and soybean (Glycine max). The disease is severe, critical, open spread and inflicts heavy yield losses annually. The objective of this study is to develop molecular markers linked to MYMIV-resistance to facilitate genotyping of urdbean and mungbean germplasms for MYMIV-reaction. Resistance-linked molecular markers were successfully developed from consensus motifs of other resistance (R) gene or R gene homologue sequences. Applying linked marker-assisted genotyping, plant breeders can carry out repeated genotyping throughout the growing season in absence of any disease incidence. Two MYMIV-resistance marker loci, YR4 and CYR1, were identified and of these two CYR1 is completely linked with MYMIV-resistant germplasms and co-segregating with MYMIV-resistant F2, F3 progenies of urdbean. The present study demonstrated that these two markers could be efficiently employed together in a multiplex-PCR-reaction for genotyping both V. mungo and V. radiata germplasms from field grown plants and also directly from the seed stock. This method of genotyping would save time and labour during the introgression of MYMIV-resistance through molecular breeding, as methods of phenotyping against begomoviruses are tedious, labour and time intensive.

Molecular marker-assisted genotyping of mungbean yellow mosaic India virus resistant germplasms of mungbean and urdbean.

Agronomic, genetic and molecular characterization of MYMIV-tolerant mutant lines of Vigna mungo.

Climate change and subsequent global temperature rise has become a threat to pulse production. Terminal heat stress results in forced maturity with low yields. The most worrying part of prediction is the estimated increase in the winter and summer temperatures by 3.2 degrees and 2.2 degrees celsius, respectively by 2050. So tolerant and early maturing germplasms that are well suited to heat stressed environment are needed to enhance and sustain lentil production in present condition. Studies were conducted to screen a large number of lentil germplasms for heat tolerance in laboratory and field condition. Seeds of forty eight cultivars of lentil were grown in plant growth chamber at 34°C with 70% relative humidity. Germination percentage was calculated. After one month survival percentage were evaluated. Germplasms were categorized according to their survival percentage as tolerant, moderately tolerant, susceptible and highly susceptible. Cell membrane thermostability test is a useful way to evaluate heat tolerance. Twenty five germplasms among the forty eight were taken to conduct the cell membrane thermostability test. Relative injury was calculated. All the germplasms were further evaluated in field condition in Baruipur Experimental farm & Udaynarayanpur. One field trial was conducted in the normal sowing condition and another in late sowing condition. Yield and survival data were recorded for all the germplasms. Considering the laboratory (including growth chamber study and cell membrane thermostability test) and field screening it was observed that Ranjan, Moitree, 14-4-1, IC 201710 and IC 208329 gave overall better performance in respect to heat tolerance.

Screening lentil (Lens culinaris Medik.) germplasms for heat tolerance

An experiment to evaluate eleven agro morphological traits in twenty three genotypes of mungbean [Vigna radiata (L.) Wilczek] in the field experiment was conducted in two consecutive years 2013 and 2014. Data were recorded on quantitative as well as visually assayed agro morphological traits including days to 50 per cent flowering, days to 1st picking of pods, days to final picking, plant height (cm), number of secondary branches per plant, number of pods per plant, pod length (cm), number of seeds per pod, 100 seed weight (g), seed yield/plant (g) and harvest index (%). All the traits were analysed using multivariate statistical analysis. Most of the important evaluated traits showed a wide range of variation. Cluster analysis using UPGMA method grouped the genotypes into five clusters. The component of mungbean genotypes among different clusters was varied from two to nine genotypes. The maximum number of genotypes i.e., 9 is found in cluster III followed by cluster IV comprising of 6 genotypes. Cluster V showed the maximum mean value for plant height, branch/plant, pods/plant, seed/pod, seed yield/plant and lowest values for days to 50% maturity, 1st picking and days to maturity. Principal component analysis revealed that the first five main PCAs amounted 71.11% of the total variation among genotypes. PC1 accounts for maximum variability in the data with respect to succeeding components.

Multivariate analysis in some genotypes of mungbean [Vigna radiata (L.) Wilczek] on the basis of agronomic traits of two consecutive growing cycles

Chickpeas play an integral role in human diet on account of their incredible nutritive value for billions of people especially in developing and under developing nations where majority of population is vegetarian either due to their choice or economic reasons (Sood et al., 2002). However, the consumption of chickpeas are restricted due to the presence of various anti-nutritional compounds such as trypsin inhibitor, chymotrypsin inhibitors, alpha amylase inhibitors, phytic acid, tannin and condensed tannin (Wang et al., 2010) which retard the nutrients availability. Trypsin and chymotrypsin inhibitors have the capacity to bind with hydrolytic enzymes, such as trypsin and chymotrypsin and impeding their International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 8 Number 01 (2019) Journal homepage: http://www.ijcmas.com

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Sabyasachi Kundagrami

Papers

Molecular marker-assisted genotyping of mungbean yellow mosaic India virus resistant germplasms of mungbean and urdbean.

Agronomic, genetic and molecular characterization of MYMIV-tolerant mutant lines of Vigna mungo.

Screening lentil (Lens culinaris Medik.) germplasms for heat tolerance

Multivariate analysis in some genotypes of mungbean [Vigna radiata (L.) Wilczek] on the basis of agronomic traits of two consecutive growing cycles

Food Processing Methods towards Reduction of Antinutritional Factors in Chickpea