Qualitative and Quantitative Evaluation of Mutants Derived by Gamma Radiation in Cowpea [Vigna unguiculata (L.) Walp]
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Date
2021-09
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G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand)
Abstract
insufficient. The present investigation was conducted to induce genetic variability in grain cowpea variety [Vigna unguiculata (L.) Walp] i.e., Pant Lobia-2, grain type, semi spreading, high proteins, and released in 2010 by SVRC Uttarakhand. The objective of this study was to identify and select agronomically desirable cowpea genotypes after mutagenesis using gamma irradiation. The seeds of pant lobia-2 were treated to 25kR (250Gy) doses of Co60 gamma radiation at Bhabha Atomic Research Centre, Trombay, Mumbai. The experiment was undertaken during Kharif Season in the year 2020-2021 at Breeder Seed Production Centre (BSPC), Pantnagar. Non irradiated plants of pant lobia-2 were used as check variety. M1 generation plants were established on a land previously ploughed, harrowed and ridged. Experiment was laid out as Randomized block design (RBD) and seeds were sown at 45x10cm spacing on 4 meters rows. All necessary cultural practices such as weeding, spraying insecticides were done timely. Observation were recorded on seven qualitative traits viz., growth habit, leaf shape, plant pubescence, flower colour, pod anthocyanin pigment, seed shape and seed colour and twelve quantitative traits viz., plant height (cm), terminal leaf length (cm), terminal leaf width (cm), peduncle length (cm), days to 50% flowering, pod length (cm), number of pods per cluster, number of pods per plant, number of seeds per pod, 100-grain weight (g), protein content (%) and yield per plant (grams) and protein estimation was done by kjeldahl method in College of Home Science, Pantnagar. Observations were recorded on M2 plants and in each line that were showing variation in characters as compared to check variety, for the estimation of data and six selected mutants named as (TA,TB,TC,TD,TE,TF and CV) were advanced to M3 generation to confirm their mutant phenotype and genetic stability. The data recorded for various quantitative traits were analyzed for analysis of variance (ANNOVA) using OPSTAT developed by O.P. sheoran, at CCS HAU, Hisar. The overall results revealed that there was increase in variability for different characters under observation of the selected mutants. However, the response of gamma radiation on individual mutant (TE) recorded highest protein content (34.05%) more than check variety PL-2. Secondly, Individual mutant (TD) seeds were bold, rhomboid in shape and recorded highest yield per plant (30.93grams) with maximum pod length (19.00cm) in comparison to other selected mutants but number of seeds and protein content was less which showed that protein content was inversely proportional to size of seeds. Among selected mutants (TA,TC,TF) that were early maturing, as a result of which due to short reproductive period it responded better with pod number and number of seeds as it has the advantage for planting in short rainfall areas also they showed better tolerance to drought, and has the ability to escape or tolerate insect damage due to short duration of vegetative period. Individual mutant (TF) recorded maximum number of pods per plant (16.33) with small seed size, along with narrow medium pod length (13.00 cm). Individual Mutant (TA) has got long peduncle and upright pods can be advanced for developing suitable plant type that is suitable for the mechanical harvesting. Individual mutant (TB) was observed with purplish pigmentation onto the pods and main stem as a result may be highly nutritious and rich in anti- oxidants. Selected Mutants (TC,TF,TE) were observed with determinate growth habit, so it has got the advantage of better interculture operations to be carried out in the field, less competition among the plants which leads to increase in yield and productivity. The novel cowpea genotypes selected through the study are valuable genetic resources for genetic enhancement and breeding.