“…In another study on 44 tomato lines, exposure to 44 • C for 4 h after 1 week of vegetative stage increased electrolyte leakage in heat-sensitive genotypes (32.92 µmhos/cm) more than heat-tolerant genotypes (22.2 µmhos/cm) (Hameed et al, 2015). Similar studies have screened tomato genotypes for heat tolerance using membrane thermostability (Sangu et al, 2015;Alsamir et al, 2017). Thus, CMT is an effective trait for identifying stable and heat-tolerant genotypes.…”
Heat Tolerance in Crops contrasting genotypes and would pave the way for characterizing the underlying molecular mechanisms, which could be valuable for engineering plants with enhanced thermotolerance. Wherever possible, we discussed breeding and biotechnological approaches for using these traits to develop heat-tolerant genotypes of various food crops.
“…In another study on 44 tomato lines, exposure to 44 • C for 4 h after 1 week of vegetative stage increased electrolyte leakage in heat-sensitive genotypes (32.92 µmhos/cm) more than heat-tolerant genotypes (22.2 µmhos/cm) (Hameed et al, 2015). Similar studies have screened tomato genotypes for heat tolerance using membrane thermostability (Sangu et al, 2015;Alsamir et al, 2017). Thus, CMT is an effective trait for identifying stable and heat-tolerant genotypes.…”
Heat Tolerance in Crops contrasting genotypes and would pave the way for characterizing the underlying molecular mechanisms, which could be valuable for engineering plants with enhanced thermotolerance. Wherever possible, we discussed breeding and biotechnological approaches for using these traits to develop heat-tolerant genotypes of various food crops.
“…The heat stress significantly affects the male reproductive organs ( Fig. 1 ) as it decreases the number of pollen grains developed and released in the anther, pollen viability, and germination ( Alsamir et al, 2017d , Rieu et al, 2017 ). Fig.…”
Section: Tomato Responses To Heat Stressmentioning
confidence: 99%
“…H-I. LA0716 showing exserted stigmata under control and high temperature conditions, respectively ( Alsamir et al, 2017d ). …”
Section: Tomato Responses To Heat Stressmentioning
Heat stress has been defined as the rise of temperature for a period of time higher than a threshold level, thereby permanently affecting the plant growth and development. Day or night temperature is considered as the major limiting factor for plant growth. Earlier studies reported that night temperature is an important factor in the heat reaction of the plants. Tomato cultivars capable of setting viable fruits under night temperatures above 21 °C are considered as heat-tolerant cultivars. The development of breeding objectives is generally summarized in four points: (a) cultivars with higher yield, (b) disease resistant varieties in the 1970s, (c) long shelf-life in 1980s, and (d) nutritive and taste quality during 1990s. Some unique varieties like the dwarf “Micro-Tom”, and the first transgenic tomato (FlavrSavr) were developed through breeding; they were distributed late in the 1980s.
High temperature significantly affects seed, pollen viability and root expansion. Researchers have employed different parameters to evaluate the tolerance to heat stress, including membrane thermo stability, floral characteristics (Stigma exertion and antheridia cone splitting), flower number, and fruit yield per plant. Reports on pollen viability and fruit set/plant under heat stress by comparing the pollen growth and tube development in heat-treated and non-heat-stressed conditions are available in literature. The electrical conductivity (EC) have been used to evaluate the tolerance of some tomato cultivars in vitro under heat stress conditions as an indication of cell damage due to electrolyte leakage; they classified the cultivars into three groups: (a) heat tolerant, (b) moderately heat tolerant, and (c) heat sensitive.
It is important to determine the range in genetic diversity for heat tolerance in tomatoes. Heat stress experiments under field conditions offer breeders information to identify the potentially heat tolerant germplasm.
“…On the contrary, plants grown without shading had the highest content of P (El-Bassiony et al, 2014). Alsamir et al (2017) reported that high temperature in tomato reduced number of fruits, flower to fruit set ratio and fresh fruit weight. These results are supporting the present inferences from our study.…”
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.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
