Abstract
High temperature induced by climatic fluctuations are an important threat for plant growth, development and quality of agricultural produces. Adaptableness to environmental changes generally derives from a large set of genetic traits affecting physio-morphological, biochemical and agronomic parameters. Therefore, the identification of genotypes with higher yield and good quality parameters at high temperatures is becoming increasingly necessary for future breeding programs. Here, we analyzed the performance of different tomato genotypes grown under elevated temperatures in terms of yield and nutritional quality of the fruit. High temperature stress was induced from flower initiation to maturity stage by keeping the pots in a temperature controlled green house facility for 45 days. The quality and yield parameters were taken at the harvesting stage. Starch and soluble sugar concentration in the leaves of tomato genotypes showed significant reduction in its amount under heat stress. Titrable acidity (TA), total soluble solids (TSS) and ascorbic acid content of tomato fruits were highest under high temperature conditions compared to ambient condition but lycopene content decreased with rise in temperature. The yield attributes viz., number of fruits/plant, fruit set %, average fruit weight (g), yield per plant (g/plant) were significantly lower for Arka Saurabh, Arka Rakshak and Pusa Rohini when compared to other genotypes under study. Molecular characterization of selected 22 tomato genotypes were assessed using 25 simple sequence repeat (SSR) markers. Phylogenetic tree was constructed by the unweighted neighbour-joining method (UPGMA) using NTSYSpc cluster analysis software. The Jaccard's similarity matrix was constructed using the SIMQUAL method using UPGMA algorithm in NTSYSpc. Jaccard's similarity matrix among these tomato genotypes ranged from a minimum of 0.22 to a maximum of 1 with an average genetic similarity of 0.67. Hence this study has importance in identifying genotypes that could maintain good quality and higher yield under high temperature condition.
Highlights
High temperature is one of the major abiotic stress affecting plants, having adverse effects on both growth and reproduction (Beena, 2013)
Twenty-five simple sequence repeat (SSR) markers were used for PCR screening, and the sequence was taken from the Sol Genomics Network database
Our study showed that an increment in Titrable acidity (TA) and total soluble solids (TSS) value were observed for all the tomato genotypes
Summary
High temperature is one of the major abiotic stress affecting plants, having adverse effects on both growth and reproduction (Beena, 2013). The relationship between the reproductive stage of tomato and the average daily temperature was studied and found that the number of fruits, fruit set percentage and fruit weight per plant decreased with increase in daily temperatures of 25–29 C (Harel et al, 2014). The knowledge of the extent of genetic variation, diversity and genetic relationships between genotypes of the crop is vital and foundation for developing an improved cultivar possessing high yield, good fruit quality and adapted to various abiotic and biotic stresses situations (Sheshshayee et al, 2011). Even though the unweighted pair group approach using arithmetic averages (UPGMA) and neighbour-joining (NJ) algorithms is intended to generate single trees, depending mostly on order of data entry, they can derive more than one topology from a single matrix
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