New early-maturing germplasm lines for utilization in chickpea improvement

Early-maturity helps chickpea to avoid terminal heat and drought and increases its adaptation especially in the sub-tropics. Breeding for early-maturing, high-yielding and broad-based cultivars requires diverse sources of early-maturity. Twenty-eight early-maturing chickpea germplasm lines representing wide geographical diversity were identified using core collection approach and evaluated with four control cultivars in five environments for 7 qualitative and 16 quantitative traits at ICRISAT Centre, Patancheru, India. Significant genotypic variance was observed for days to flowering and maturity in all the environments indicating scope for selection. Genotypes × environment interactions were significant for days to flowering and maturity and eight other agronomic traits. ICC 16641, ICC 16644, ICC 11040, ICC 11180, and ICC 12424 were very early-maturing, similar to or earlier than control cultivars Harigantars and ICCV 2. The early-maturing accessions produced on average 22.8% more seed yield than the mean of four control cultivars in the test environments. ICC 14648, ICC 16641 and ICC 16644 had higher 100-seed weight than control cultivars, Annigeri and ICCV 2. Cluster analysis delineated three clusters, which differed significantly for all the traits. First cluster comprised three controls, ICCV 96029, Harigantars, ICCV 2 and two germplasm lines, ICC 16644 and ICC 16641, second cluster comprised 13 germplasm lines and control cultivar Annigeri, and third cluster comprised 13 germplasm lines. Maturity was main basis of delineation of the first cluster from others. Plot yield and its associated traits were the main basis for delineation of the second cluster

Reference genes for quantitative reverse transcription-polymerase chain reaction expression studies in wild and cultivated peanut

<p>Abstract</p> <p>Background</p> <p>Wild peanut species (<it>Arachis </it>spp.) are a rich source of new alleles for peanut improvement. Plant transcriptome analysis under specific experimental conditions helps the understanding of cellular processes related, for instance, to development, stress response, and crop yield. The validation of these studies has been generally accomplished by quantitative reverse transcription-polymerase chain reaction (qRT-PCR) which requires normalization of mRNA levels among samples. This can be achieved by comparing the expression ratio between a gene of interest and a reference gene which is constitutively expressed. Nowadays there is a lack of appropriate reference genes for both wild and cultivated <it>Arachis</it>. The identification of such genes would allow a consistent analysis of qRT-PCR data and speed up candidate gene validation in peanut.</p> <p>Results</p> <p>A set of ten reference genes were analyzed in four <it>Arachis </it>species (<it>A. magna</it>; <it>A. duranensis</it>; <it>A. stenosperma </it>and <it>A. hypogaea</it>) subjected to biotic (root-knot nematode and leaf spot fungus) and abiotic (drought) stresses, in two distinct plant organs (roots and leaves). By the use of three programs (GeNorm, NormFinder and BestKeeper) and taking into account the entire dataset, five of these ten genes, <it>ACT1 </it>(actin depolymerizing factor-like protein), <it>UBI1 </it>(polyubiquitin), <it>GAPDH </it>(glyceraldehyde-3-phosphate dehydrogenase), <it>60S </it>(60S ribosomal protein L10) and <it>UBI2 </it>(ubiquitin/ribosomal protein S27a) emerged as top reference genes, with their stability varying in eight subsets. The former three genes were the most stable across all species, organs and treatments studied.</p> <p>Conclusions</p> <p>This first in-depth study of reference genes validation in wild <it>Arachis </it>species will allow the use of specific combinations of secure and stable reference genes in qRT-PCR assays. The use of these appropriate references characterized here should improve the accuracy and reliability of gene expression analysis in both wild and cultivated Arachis and contribute for the better understanding of gene expression in, for instance, stress tolerance/resistance mechanisms in plants.</p