Dissecting the Heat Stress Responses and Effects on Morphology of Tomato Varieties Employing Pre-transplant High Temperature Conditioning
Dissecting the Heat Stress Responses and Effects on Morphology of Tomato Varieties Employing Pre-transplant High Temperature Conditioning
Gulzar Ullah* and Gohar Ayub
ABSTRACT
An experiment was conducted to investigate the influence of heat pretreatment conditioning durations (control or no heat pretreatment,10 hrs,15 hrs and 20 hrs) on three tomato varieties (Roma, Rio Grande and Yaqui) sown at Horticulture Research Farm, Department of Horticulture, The University of Agriculture Peshawar during 2017 and 2018. Completely Randomized Design (CRD) in growth chamber before transplantation and Randomized Complete Block Design (RCBD) with two factors and three replications after transplanting to the field were used. Tomato seedlings at their 4-leaf stage were subjected to a 350C temperature stress for 10, 15 and 20 hrs as a pre-transplant hardening method. Both groups HP (heat pretreatment) and NHP (Non-heat pretreatment or Control) were then transplanted to the field. Results revealed that different heat pretreatment durations and varieties significantly affected the growth and yield of tomato. Regarding heat pretreatment durations, number of flower clusters plant-1 (16.06), fruit set percentage (68.33%), number of flowers cluster-1 (8.34), chlorophyll content (50.31 SPAD), leaf relative water content (75.34%), Putrescine concentration (193.95 nmol/g), spermidine concentration (154.59 nmol/g), spermine concentration (36.51 nmol/g), yield (20.14 t ha-1), early flowering (26.99 days) and lowest electrolyte leakage (48.87%) was observed in plants treated with 20 hours heat pretreatment duration as compared to other heat pretreatment durations and control. Concerning tomato varieties, number of flower clusters plant-1 (16.99), fruit set percentage (68.25%), number of flowers cluster-1 (7.91), chlorophyll content (48.06 SPAD), leaf relative water content (80.68%), Putrescine concentration (190.25 nmol/g), spermidine concentration (152.57 nmol/g), yield (21.00 t ha-1) and lowest electrolyte leakage (48.86%) was recorded for Rio Grande as compared to Roma and Yaqui. Also highest spermine concentration (35.72 nmol/g) and early flowering (26.72 days) resulted in Roma as compared to Rio Grande and Yaqui. The interaction effects of heat pretreatment duration and varieties were non-significant for most of the attributes studied except chlorophyll content and number of flower clusters plant-1. It can be concluded that heat pretreatment of 350C for 20 hours and Rio Grande variety resulted in enhanced growth, biochemical attributes and production of tomato in the agro-climatic conditions of Peshawar.
To share on other social networks, click on any share button. What are these?
