Physiological responses of groundnut (Arachis hypogaea L.) to drought stress and its amelioration: A review

2003 ◽  
Vol 51 (2) ◽  
pp. 205-227 ◽  
Author(s):  
T. Y. Reddy ◽  
V. R. Reddy ◽  
V. Anbumozhi

Groundnut (Arachis hypogaea L.) is an important cash crop for tropical farmers. It is an annual legume and its seeds contain high amounts of edible oil (43-55%) and protein (25-28%). Even though it is fairly drought-tolerant, production fluctuates considerably as a result of rainfall variability. To develop a water stress response function in groundnut, research has been done to improve the performance under varying degrees of stress at various physiological stages of crop growth. This review summarizes recent information on the drought resistance characteristics of groundnut with a view to developing appropriate genetic enhancement strategies for water-limited environments. It is suggested that there are considerable gains to be made in increasing yield and stabilizing the yield in environments characterized by terminal drought stress and further exploiting drought escape strategy, by shortening crop duration. Many traits conferring dehydration avoidance and dehydration tolerance are available, but integrated traits, expressed at a high level of organization, are likely to be more useful in crop improvement programs. Possible genetic improvement strategies are outlined, ranging from empirical selection for yield in drought environments to a physiological-genetic approach. It is also suggested that in view of recent advances in understanding drought resistance mechanisms, the latter strategy is becoming more feasible. It is concluded that the use of this recently derived knowledge in a systematic manner could lead to significant gains in yield and yield stability in the world's groundnut production. Research is needed to develop transferable technologies to help farmers in arid and semi-arid regions. Increasing soil moisture storage by soil profile management and nutrient management for quick recovery from drought are some of the areas which need to be explored.

Genome ◽  
2000 ◽  
Vol 43 (4) ◽  
pp. 656-660 ◽  
Author(s):  
V Subramanian ◽  
S Gurtu ◽  
R C Nageswara Rao ◽  
S N Nigam

Construction of a genetic linkage map is necessary to apply marker-assisted selection tools in a crop improvement program. Except for the recent studies from two laboratories, most of the previous studies have shown little or no DNA polymorphism in cultivated groundnut (Arachis hypogaea L.). In the present study, 70 selected genotypes, representing variability for several morphological, physiological, and other characters, were studied for polymorphism employing random amplified polymorphic DNA (RAPD) assay with 48 oligonucleotide primers. Of the 48 oligonucleotide primers only 7 (14.6%) yielded polymorphic amplification products. The total number of bands from the 7 primers was 408, of which 27 were polymorphic. Detection of polymorphism in cultivated groundnut opens up the possibility of development of its molecular map by judicious selection of genotypes that show DNA polymorphism. This approach will be useful for developing marker-assisted selection tools for genetic enhancement of groundnut for desirable traits.Key words: Arachis hypogaea L., RAPD, DNA polymorphism, oligonucleotide, random primers.


Author(s):  
Nathan T Hein ◽  
Ignacio A Ciampitti ◽  
S V Krishna Jagadish

Abstract Flowering and grain-filling stages are highly sensitive to heat and drought stress exposure, leading to significant loss in crop yields. Therefore, phenotyping to enhance resilience to these abiotic stresses is critical for sustaining genetic gains in crop improvement programs. However, traditional methods for screening traits related to these stresses are slow, laborious, and often expensive. Remote sensing provides opportunities to introduce low-cost, less-biased, high-throughput phenotyping methods to capture large genetic diversity to facilitate enhancement of stress resilience in crops. This review focuses on four key physiological traits or processes that are critical in understanding crop responses to drought and heat stress during reproductive and grain-filling periods. Specifically, these traits include: i) time-of-day of flowering, to escape these stresses during flowering, ii) optimizing photosynthetic efficiency, iii) storage and translocation of water-soluble carbohydrates, and iv) yield and yield components to provide in-season yield estimates. An overview of current advances in remote sensing in capturing these traits, limitations with existing technology and future direction of research to develop high-throughput phenotyping approaches for these traits are discussed in this review. In the future, phenotyping these complex traits will require sensor advancement, high-quality imagery combined with machine learning methods, and efforts in transdisciplinary science to foster integration across disciplines.


Author(s):  
Pallavi Sinha ◽  
Vikas K. Singh ◽  
Abhishek Bohra ◽  
Arvind Kumar ◽  
Jochen C. Reif ◽  
...  

Abstract Key message Integrating genomics technologies and breeding methods to tweak core parameters of the breeder’s equation could accelerate delivery of climate-resilient and nutrient rich crops for future food security. Abstract Accelerating genetic gain in crop improvement programs with respect to climate resilience and nutrition traits, and the realization of the improved gain in farmers’ fields require integration of several approaches. This article focuses on innovative approaches to address core components of the breeder’s equation. A prerequisite to enhancing genetic variance (σ2g) is the identification or creation of favorable alleles/haplotypes and their deployment for improving key traits. Novel alleles for new and existing target traits need to be accessed and added to the breeding population while maintaining genetic diversity. Selection intensity (i) in the breeding program can be improved by testing a larger population size, enabled by the statistical designs with minimal replications and high-throughput phenotyping. Selection priorities and criteria to select appropriate portion of the population too assume an important role. The most important component of breeder′s equation is heritability (h2). Heritability estimates depend on several factors including the size and the type of population and the statistical methods. The present article starts with a brief discussion on the potential ways to enhance σ2g in the population. We highlight statistical methods and experimental designs that could improve trait heritability estimation. We also offer a perspective on reducing the breeding cycle time (t), which could be achieved through the selection of appropriate parents, optimizing the breeding scheme, rapid fixation of target alleles, and combining speed breeding with breeding programs to optimize trials for release. Finally, we summarize knowledge from multiple disciplines for enhancing genetic gains for climate resilience and nutritional traits.


2020 ◽  
Vol 71 (19) ◽  
pp. 6092-6106 ◽  
Author(s):  
Ping-Xia Zhao ◽  
Zi-Qing Miao ◽  
Jing Zhang ◽  
Si-Yan Chen ◽  
Qian-Qian Liu ◽  
...  

Abstract Drought is one of the most important environmental factors limiting plant growth and productivity. The molecular mechanisms underlying plant drought resistance are complex and not yet fully understood. Here, we show that the Arabidopsis MADS-box transcription factor AGL16 acts as a negative regulator in drought resistance by regulating stomatal density and movement. Loss-of-AGL16 mutants were more resistant to drought stress and had higher relative water content, which was attributed to lower leaf stomatal density and more sensitive stomatal closure due to higher leaf ABA levels compared with the wild type. AGL16-overexpressing lines displayed the opposite phenotypes. AGL16 is preferentially expressed in guard cells and down-regulated in response to drought stress. The expression of CYP707A3 and AAO3 in ABA metabolism and SDD1 in stomatal development was altered in agl16 and overexpression lines, making them potential targets of AGL16. Using chromatin immunoprecipitation, transient transactivation, yeast one-hybrid, and electrophoretic mobility shift assays, we demonstrated that AGL16 was able to bind the CArG motifs in the promoters of the CYP707A3, AAO3, and SDD1 and regulate their transcription, leading to altered leaf stomatal density and ABA levels. Taking our findings together, AGL16 acts as a negative regulator of drought resistance by modulating leaf stomatal density and ABA accumulation.


2021 ◽  
Vol 50 (2) ◽  
pp. 289-294
Author(s):  
Muhammad Sajjad Iqbal ◽  
Abdul Ghafoor

Study revealed a first report of proteomics variation in Nigella sativa L. based on analyzing 32 accessions through SDS-PAGE. Three prominent regions along eight subunits were identified. Intra specific variation was observed low whereas the sharpness of bands was high between first and second regions. It was noted that in second region there was no clear evidence of band formation in N. sativa. Prominent and sharp protein peptide bands were recorded in four accessions, namely PK-020561, PK-020609, PK-020620 and PK-020646. Further investigation of single seeds showed almost similar genetic pattern within the single accession. Five clusters were formed on the basis of Euclidean distance. Cluster-I & II contain 1, 1 accession each, likewise Cluster-III and C-IV contain 2, 2 accessions whereas Cluster-V was found diversified as consisted of 26 accessions. Two accessions PK-020878 and PK-020877 were recommended for polymorphism and crop improvement programs. Bangladesh J. Bot. 50(2): 289-294, 2021 (June)


2021 ◽  
Author(s):  
Yang Cao ◽  
fei song ◽  
Xingtang Zhao ◽  
Liming He ◽  
Yaguang Zhan

Abstract Background: In this study, sodium nitrate (SNP, a donor of nitric oxide) and methyl jasmonate (MJ) were used as exogenous hormones. The experiment was conducted with the offspring (interspecific hybrid) D110 of ash and ash, and their respective parents (non-interspecific hybrid) D113 and 4-3 as experimental materials. The experiment set up three experimental groups of drought stress, exogenous hormone SNP and MJ, and a control group under normal growth (non-drought stress), to study the physiological indicators and gene expression of manchurian ash. Result: The results showed that under drought stress and exogenous application of hormone SNP or MJ, there were significant differences between hybrids and parents in plant growth, photosynthesis, defense enzyme activity, hormone content and gene expression.Conclusions: This experiment provides a new theoretical support for the existing hormone breeding methods of manchurian ash, which can improve the drought resistance of manchurian ash and increase its survival rate in the wild. Increasing the growth rate and breeding efficiency of manchurian ash brings new ideas.


Author(s):  
Ali Hussain Al Lawati ◽  
Saleem Kaseemsaheb Nadaf ◽  
Nadiya Abubakar Al Saady ◽  
Saleh Ali Al Hinai ◽  
Almandhar Almamari ◽  
...  

Oman is endowed with enormous diversity of important food crops that have global significance for food security and has ancient history of cultivation of bread wheat (Triticum aestivum L.) with its divergent landraces, which are useful in crop improvement. 55 indigenous Omani accessions conserved at the USDA were evaluated in the winter season (November to April) of the years 2017-2018 and 2018-2019 on loamy soil under sprinklers in augmented design with 5 check varieties in 5 replications following crop husbandry practices as per national recommendations using 9 quantitative (descriptors) and 6 qualitative traits (anthocyanin pigmentation on plant parts). The data on traits were subjected not only for PC values and D values after varimax rotation through Kaiser normalization in Principal Component Analysis (PCA) but also for Agglomerative Hierarchical Clustering (AHC). The results indicated that indigenous bread wheat accessions were significantly different (p>0.05) for all the quantitative traits except number of tillers. The multivariate analyses led to formation of four diverse clusters from PCA analyses corresponding to four quadrants of bi-plot graphs and three clusters from AHC analysis corresponding to main clades of dendrogram. The parents were selected from common accessions of distinct clusters in all the multivariate analyses for hybridization for improving characters of growth for higher yield or productivity with pigmentation on one or two plant parts useful for DUS test of varieties. The indigenous bread wheat landraces / accessions were genetically diverse and have potential for use in national crop improvement programs for earliness and higher grain productivity with distinct identification markers.


2020 ◽  
Author(s):  
Shipeng Yang ◽  
Lihui Wang ◽  
Qiwen Zhong ◽  
Guangnan Zhang ◽  
Haiwang Zhang ◽  
...  

Abstract Background Jerusalem artichoke (Helianthus tuberosus L.) is a highly stress-resistant crop, especially it grows normally in the desertified land of Qinghai-Tibet Plateau in the past two years, and has become a crop with agricultural, industrial and ecological functions. However, there are few studies on drought resistance of Jerusalem artichoke at present, and studies on the mechanisms of stress resistance of Jerusalem artichoke breeding and fructan are seriously lagging behind. In this study, we selected two differentially resistant cultivars for drought stress experiments with different concentration gradients, the aim was finding DEGs and metabolic pathways associated with drought stress. Results Based on an additional analysis of the metabolic pathways under drought stress using MapMan, the most different types of metabolism included secondary metabolism, light reaction metabolism and cell wall. As a whole, QY1 and QY3 both had a large number of up-regulated genes in the flavor pathway. It was suggested that flavonoids could help Jerusalem artichoke to resist drought stress and maintain normal metabolic activities. In addition, the gene analysis of the abscisic acid (ABA) key metabolic pathway showed that QY3 had more genes in NAC and WRKY than QY1, but QY1 had more genes in response to drought stress as a whole. By combining RNA-Seq and WGCNA, a weighted gene co-expression network was constructed and divided into modules. By analyzing specifically the expressed modules, four modules were found to have the highest correlation with drought. Further research on the genes revealed that all 16 genes related to histone, ABA and protein kinase had the highest significance in these pathways. Conclusions These findings represent the first RNA-Seq analysis of drought stress in Jerusalem artichoke, which is of substantial significance to explore the function of drought resistance in Jerusalem artichoke and the excavation of related genes.


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