Assessment of drought responses of chilli [capsicum annum L.] genotypes by using modern plant phenomics tools
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Date
2019-05-31
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Vasantrao Naik Marathwada Krishi Vidyapeeth, Parbhani
Abstract
Although the Global temperature has increased, it is expected to increase further in the next century. The annual daily maximum temperatures are projected to increase at the rate of 30C by mid-21st century and about 50C by the late 21st century. This would result in a more recurrent and extreme drought events in many parts of the world. To face this problem, there is a great need to identify the different genotypes which can withstand drought stress and yield sustainably (Annex, I, 2012; Sherwood et al., 2013). Hence the present investigation was undertaken to study the performance of different chilli genotypes under depleting soil moisture conditions which occurs during drought. Above experiment was set in pots and the evaluation of genotypes was done by adopting conventional as well as modern image based approaches. Eight genotypes viz., Parbhani Tejas, Parbhani Mirchi, Phule Jyoti, Jayanti, Hirkani, Arka Lohit, Arka Suphal and Local Genotype were sown in a pots with three stress treatments viz., non-stress (control), stress at flowering and stress at fruit development, with two replications. In addition to this, same genotypes were used to study the influence of depleting soil moisture level on shoot traits. Present investigation was conducted at National Institute of Abiotic Stress Management (18° 09’ 30.62’’N; 74° 30’ 03.08’’E; MSL 570m), Malegaon (Baramati), Dist.- Pune during Rabi season of 2018.
Observations were recorded on growth, leaf, physiological, phenological, fruit, yield and quality parameters. Along with all these parameters, plants responses also captured through different imaging systems by employing plant phenomics facility. Results showed that drought stress imposed at flowering and fruit development stage; adversely affected growth and physiological processes of plants of all genotypes which resulted in decreased commercial yield. Drought stress imposed at flowering stage was found to be the most effective on restricting the growth and inducing major flower drop, which was ultimately resulted into decreased yield as compared to yield under non-stress condition. However, plants which were subjected to drought stress at stage of fruit development produced fruits of shortest length and having less fruit weight with more pungency while these fruits had low ascorbic acid content. Physiological parameters were significantly affected by stress imposed at both growth stages. Physiological traits like RWC, chlorophyll content, chlorophyll fluorescence, stomatal conductance, NDVI, SPAD index were sustainably less under stress conditions; however, canopy temperature and proline content were relatively high as compared those under non stress conditions. This negative impact on physiological parameters can be used as an indicator of magnitude of stress and as predictor of yield potential of genotypes under stressed conditions. From the recorded observations, it is evident that the genotype – Parbhani Mirchi was less influenced under drought stress as compared to other genotypes. Parbhani Mirchi was found to be the tallest genotype and could maintain physiological status even under stress conditions.
Image based parameters also revealed that Parbhani Mirchi was less affected under depleted soil moisture conditions. Shoot architecture of plants were studied by visible images however tissue water level of genotypes were interpreted from NIR images. Shoot architecture of plants were studied by interpreting the data generated from parameters like area, caliper length and digital volume. Image based data revealed that Parbhani Mirchi was more efficient in maintaining its shoot architecture even under stressed conditions as compared to other genotypes. Parabhni Mirchi also preserved its tissue water level under stressed condition.
Parbhani Mirchi showed higher shoot dry weight and biomass under both control and stressed conditions as revealed by conventional and phenomics methods. Hence, it may be concluded that, Parbhani Mirchi was the most promising among selected eight genotypes.
Overall, from the present study it is evident that Parbhani Mirchi has outstanding performance among all the eight genotypes tested. Therefore the genotype can be considered suitable for sustainable cultivation of chilli crop in water stress-prone areas of the country. This experiment was carried out for only one time hence to make any standard recommendations, same trial should be repeated. Additionally the genotype also appears suitable as parent in breeding experiments that are targeted towards stress tolerance and yield improvement in chilli.
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