Dorin Gupta

Evaluation of Wild Lens Taxa for Agro-Morphological Traits, Fungal Diseases and Moisture Stress in North Western Indian Hills

Exploitation of wild gene pool for breeding is a common practice in an increasing number of cultivated plants. The cultivated lentil could not attain the substantial improvement in the yield potential due to loss of genes for higher productivity and lack of resistance against biotic and abiotic stresses. The absence of evaluation data of wild lentils for characters of economic importance, besides biotic and abiotic stresses, is one of the constraints in their use in lentil breeding programme. In the present study, 70 wild accessions from four wild Lens subsp./sp. (L. culinaris subsp. orientalis, L. odomensis, L. ervoides and L. nigricans) along with 3 checks (Precoz, PL-406 and PL-639) were evaluated for phenological and agro-morphological characters, for their reaction to three fungal diseases (wilt, powdery mildew and rust) and screened for tolerance to moisture stress. The wild accessions showed higher performance for branches/plant as compared to cultivated genotypes. Similarly, a few accessions of L. culinaris subsp. orientalis were earlier to flower and had higher seeds and seed yield/plant as compared to cultivated lentil. However, some were comparable with cultivated genotypes for flowers/peduncle, peduncle length and plant height. The mean performance for flowers per peduncle, leaflets per leaf, plant height, seeds and seed yield per plant increased, while decreased for days to flowering and maturity, and branches per plant during the evolution of cultivated lentil from the wild Lens taxa. Of Lens taxa, L. nigricans had the maximum resistant accessions for biotic and tolerance to abiotic stresses. The valuable variation existing among wild accessions can be exploited following introgression with cultivated lentils. It will help in the flow of useful genes from wild to cultivated lentil for generating wide spectrum of variability and its subsequent use in genetic restructuring of lentil.

Is lithium biologically an important or toxic element to living organisms? An overview

Industrialized world is exposing living organisms to different chemicals and metals such as lithium (Li). Due to their use in common household items to industrial applications, it is imperative to examine their bioavailability. Lithium belongs to the group IA and also has wider uses such as in batteries, air conditioners to atomic reactors. Lithium occurs naturally in soil and water, mostly at low concentrations, and enters the food chain. It is not one of the essential minerals though various studies indicate that low levels of Li have beneficial effects on living organisms, whereas high levels expose them to toxicity and related detrimental effects. This review suggests that Li could be biologically important to living organism depending upon its concentration/exposure. Little is known about its biological importance and molecular understanding of its accumulation and mode of action, which might have future implications for Li’s long-term effects on living organisms.

Silicon improves seed germination and alleviates drought stress in lentil crops by regulating osmolytes, hydrolytic enzymes and antioxidant defense system

Silicon (Si) has been widely reported to have beneficial effect on mitigating drought stress in plants. However, the effect of Si on seed germination under drought conditions is still poorly understood. This research was carried out to ascertain the role of Si to abate polyethylene glycol-6000 mediated drought stress on seed germination and seedling growth of lentil. Results showed that drought stress significantly decreased the seed germination traits and increased the concentration of osmolytes (proline, glycine betaine and soluble sugars), reactive oxygen species (hydrogen peroxide and superoxide anion) and lipid peroxides in lentil seedlings. The activities of hydrolytic enzymes and antioxidant enzymes increased significantly under osmotic stress. The application of Si significantly enhanced the plants ability to withstand drought stress conditions through increased Si content, improved antioxidants, hydrolytic enzymes activity, decreased concentration of osmolytes and reactive oxygen species. Multivariate data analysis showed statistically significant correlations among the drought-tolerance traits, whereas cluster analysis categorised the genotypes into distinct groups based on their drought-tolerance levels and improvements in expression of traits due to Si application. Thus, these results showed that Si supplementation of lentil was effective in alleviating the detrimental effects of drought stress on seed germination and increased seedling vigour.

A Novel Lens orientalis Resistance Source to the Recently Evolved Highly Aggressive Australian Ascochyta lentis Isolates

Substantial yield losses and poor seed quality are frequently associated with Ascochyta blight infection of lentil caused by Ascochyta lentis. Recently reported changes in aggressiveness of A. lentis have led to decreased resistance within cultivars, such as Northfield and Nipper in Australia. Furthermore, the narrow genetic base of the current breeding program remains a risk for further selective pathogen evolution to overcome other currently used resistances. Therefore, incorporation of potentially novel and diverse resistance genes into the advanced lines will aid to improve cultivar stability. To identify these, 30 genotypes sourced from five wild species (Lens orientalis, L. odomensis, L. ervoides, L. nigricans and L. lamottei), including eight previously reported resistance sources, were screened for disease reaction to two recently isolated and highly aggressive isolates. Subsequently, two L. orientalis accessions were found highly resistant and a further six L. nigricans, one L. odomensis, one L. ervoides, one L. lamottei, and one L. orientalis accessions were moderately resistant. Several of these were more resistant than the currently deployed resistance source, ILL 7537. Furthermore, L. orientalis accession ILWL 180 was consistently resistant against other highly aggressive isolates recovered from diverse geographical lentil growing regions and host genotypes, suggesting stability and potential for future use of this accession in the Australian lentil breeding program.

Assessment of Triticale (Triticosecale) X Bread Wheat (Triticum Aestivum) Genotypes for Drought Tolerance Based on Morpho-Physiological, Grain Yield and Drought Tolerance Indices Under Non-Irrigated and Irrigated Environments

Wheat being important staple crop urges the need to evaluate and develop new drought-tolerant varieties to sustain its productivity under changing climatic conditions. Therefore, this study was conducted to assess the differential morpho-physiological, grain yield and drought tolerance indices responses of 27 triticale x bread wheat genotypes along with eight checks under non-irrigated and irrigated environments in randomized complete block design with three replications. Data on 12 important morpho-physiological and grain yield related traits along with revealed sufficient variability under two environments. Among various traits magnitude of heritability and genetic advance indicated that selection of flag-leaf area, spikes per plant and 1000-grain weight could respond to higher grain yield under non-irrigated environment. Seedling stage traits viz., germination percentage, root length, shoot length, seedling vigour index (SVI) and germination index (GI) under normal (0 bar) and simulated water stress with Polyethylene glycol at -8 bar indicated greater sensitivity of the genotypes to water stress. Five drought tolerance indices viz.,drought susceptibility index (DSI), tolerance index (TOL), stress tolerance index (STI), yield index (YI) and yield stability index (YSI) were also calculated to identify drought tolerant and stable genotypes based on their yields under two environ- ments. Minimum value of DSI, TOL and yield reduction and maximum value of YSI were in harmony with each other to categorized RL 135-P1 RL 22-144 A, RL-110-1P1, RL 128-1 P1 and RL 118-P1 as top five promising drought tolerant and yield stable genotypes. These genotypes could potentially be utilized for drought tolerance wheat breeding program.

The use of infrared thermal imaging as a non-destructive screening tool for identifying drought-tolerant lentil genotypes

Lentil (Lens culinaris, Medik.) is an important legume crop, which often experience drought stress especially at the flowering and grain filling phenological stages. The availability of efficient and robust screening tools based on relevant non-destructive quantifiable traits would facilitate research on crop improvement for drought tolerance. The objective of this study was to evaluate the drought tolerance of 37 lentil genotypes using infrared thermal imaging (IRTI), drought tolerance parameters and multivariate data analysis. Potted plants were kept in a completely randomized design in a growth chamber with five replicates. Plants were subjected to three different drought treatments: 100, 50 and 20% of field capacity at the onset of reproductive period. The relative drought stress tolerance was determined based on a set of morpho-physiological parameters including non-destructive measures based on IRTI, such as: canopy temperature (Tc), canopy temperature depression (CTD) and crop water stress index (CWSI) during the growing period and destructive measures at harvest, such as: dry root-shoot ratio (RS ratio), relative water content (RWC) and harvest index (HI). The drought tolerance indices used were drought susceptibility index (DSI) and drought tolerance efficiency (DTE). Results showed that drought stress treatments significantly reduced the RWC, HI, CTD and DSI, whereas, the values of Tc, CWSI, RS ratio and DTE significantly increased for all the genotypes. The cluster analysis from morpho-physiological parameters clustered genotypes in three distinctive groups as per the level of drought stress tolerance. The genotypes with higher values of RS ratio, RWC, HI, DTE and CTD and lower values of DSI, Tc and CWSI were identified as drought-tolerant genotypes. Based on this preliminary screening, the genotypes Digger, Cumra, Indianhead, ILL 5588, ILL 6002 and ILL 5582 were identified as promising drought-tolerant genotypes. It can be concluded that the IRTI analysis is a high-throughput constructive screening tool along with RS ratio, RWC, HI and other drought tolerance indices to define the drought stress tolerance variability within lentil plants. These results provide a foundation for future research directed at identifying powerful drought assessment traits using rapid and non-destructive techniques, such as IRTI along with the yield traits, and understanding the biochemical and molecular mechanisms underlying lentil tolerance to drought stress.

Evidence of early defence to Ascochyta lentis within the recently identified Lens orientalis resistance source ILWL180

R. H. R. Dadu , R. Ford, P. Sambasivam and D. Gupta* School of Agriculture and Food, Faculty of Veterinary and Agriculture Sciences, The University of Melbourne, Dookie Campus, Vic.; Environmental Futures Research Institute, School of Natural Sciences, Griffith University, Nathan Campus, Qld; and Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville Campus, Vic., Australia

Assessing genetic potential of elite interspecific and intraspecific advanced lentil lines for agronomic traits and their reaction to rust (Uromyces viciae-fabae)

Abstract. The narrow genetic base of lentil (Lens culinaris) has challenged the efforts of breeders to increase its productivity under changing environmental conditions. Inclusion of wild species and diverse cultivated genotypes offers an opportunity to generate new variation through wide hybridisation to broaden the genetic base of cultivated lentil. We evaluated 96 elite, interspecific (L. culinaris × L. orientalis) and intraspecific advanced lentil genotypes along with four checks to determine the extent of genetic variation, resistance to lentil rust (Uromyces viciae-fabae), and the nature and magnitude of their genetic divergence. Sufficient genetic variability was revealed for all of the traits. High heritability and genetic advance were recorded for number of seeds per pod, number of pods per plant, seed yield per plant and biomass per plant. A positive correlation was recorded between grain yield and ten important plant traits. Statistical (D2) and molecular analyses grouped all genotypes into two main clusters and revealed sufficient genetic diversity among advanced lines. Our study showed promising results for creating new variation through wide hybridisation and identified lines L-354 and L-437-1 (rust-resistant) and HPLL-32 (moderately rust-resistant) superior for seed yield and related traits.

A Comprehensive Study of Variation in Selected QPM and Non-QPM Maize Inbred Lines

To enhance the nutritional value of maize (Zea mays L.), genetic characterization and conversion of common maize into crop enriched with quality protein maize may be beneficial. With the hope of producing a superior maize cultivar, the pattern of relationship among 40 maize inbred lines (QPM and non-QPM) adapted to hills was examined using molecular, biochemical and morphological characteristics. Among the non-QPM set, early maturing lines BAJIM-08-26 and KI-30 were found superior for grain yield, and among QPM set, CML189 line was found superior for high tryptophan content. Phenotypic performance-based clustering using Mahalanobis distance revealed seven clusters. Genotypes were grouped on the basis of flowering and yield traits. Two major clusters were defined, one consisting of all QPM lines and other have all non-QPM lines. This distinction is well observed in the plot generated by principal component analysis. This information may be used in selecting genetically divergent lines for ongoing breeding programs for quality enhancement. The selected QPM line(s) could be used as donor and the well-adapted agronomically superior lines as recurrent parent for conversion of non-QPM to QPM lines.

Effect of microwave (2.45 GHz) treatment of soil on yield components of wheat (Triticum aestivum L.)

ABSTRACT Pre-sowing microwave (MW) irradiation (2.45 GHz) of soil for 120 s was investigated for sustainably enhancing wheat yield. A two-factor factorial glasshouse experiment was conducted to explore the bio-stimulation effect of MW energy on wheat crop growth and yield. The 175% increase in dry biomass and 96% incremental increase in grain yield of wheat were obtained through the application of 2.45 GHz MW energy to soil at N1 (0 mg N pot –1) compared to non-microwave treated soil. The MW irradiation of soil holds potential to significantly enhance wheat productivity.