Dr. Prasanna Kademane holds a Ph D in Horticulture from the University of Agriculture Science, Bangalore, India. He has worked as tomato breeder in Monsanto Vegetables (now part of Bayer) in India since 2003. During his tenure as tomato breeder, he established systematic breeding program with high level technology integration, releasing several tomato hybrids from the breeding program, most popular ones are Abhilash, Ayushman, Saksham and Ansal. He held the responsibility of managing India Veg R&D from 2016-2018 and currently is the Head of Vegetable Breeding and Testing for Asia in Bayer.
Potential of Germplasm diversity for Evolving Heat Set in Tomato
Global climate change and growing food demand have become two of the major challenges in agriculture in the recent time. The global warming poses a larger risk for crop productivity which demands development of strategies to substantially improve food availability. Adaptation of agriculture to climate change includes adjustment of planting and harvest times, expansion of croplands to more permissive areas, changing genotypes or species to those with more appropriate thermal time or heat stress tolerance, developing new germplasm with improved traits, altering agronomic practices, and using climate forecasting to reduce production risks.
In tomato, which is an important horticultural crop consumed worldwide, high temperatures can negatively affect the vegetative and reproductive growth phases, resulting in up to 70% tomato harvest losses. While high temperature affects the whole plant, development of the male gametophyte, the pollen, seems to be the most sensitive process. It has been reported that for tomatoes, when the temperature exceeds 35 °C, seed germination, seedling and vegetative growth, flowering and fruit set, as well as fruit ripening, are adversely affected. So, appropriate strategies need to be developed in order to limit the negative impact of high temperatures on fruit set in tomatoes, in the global regions that will likely experience increases in temperatures due to global warming. Besides the choice of the best management practices, the selection of heat tolerant genotypes could work to mitigate the decrease of tomato yield grown under unfavorable temperatures.
Exploiting the phenotypic and genomic variations of tomato germplasm for heat tolerance through appropriate techniques provides a great opportunity to select favorable alleles contributing to higher yield under high temperature conditions. Since the response to heat stress is a very complex genetic trait, molecular markers targeting quantitative trait loci (QTLs) and genes involved in the heat tolerance might aid the selection of genotypes tolerant to high temperatures.
The aspects of high temperature impact on the growth and development of plants, methods to screen for heat set, impact on trait correlations, exploiting genetic and genomic resources to enhance heat-tolerance, advanced technology interventions to create and exploit genetic variability for heat tolerance are discussed. In addition, a list of germplasm for heat tolerance is presented.