Heat stress-induced changes in shoot and root characteristics of genotypes of tepary bean (Phaseolus acutifolius A. Gray), common bean (Phaseolus vulgaris L.) and their interspecific lines

Ligia Carmenza Muñoz,Jaime E Muñoz,Mariela Rivera,Fatma Sarsu,Idupulapati M Rao

doi:10.21475/ajcs.21.15.09.sp-6

Abstract

Heat stress is a major limitation to grain yield in common bean (Phaseolus vulgaris L.). Tepary bean (Phaseolus acutifolius A. Gray) is better adapted to heat stress than common bean. Ten tepary bean accessions, four common bean genotypes and four interspecific lines involving P. vulgaris and P. acutufolius, P. coccineus and P. dumosus were evaluated for tolerance to heat stress conditions induced under greenhouse conditions and these were compared to plants grown under ambient temperatures. The high temperature treatment was 29 ±5 °C during the day and was >24 °C (up to 27 °C) during the night, while the ambient temperature (AT) treatment was 25 ±5 °C during the day and 19± 2 °C at night. The genotypic differences were evaluated for morpho-physiological characteristics of shoot and root and also yield components. The Genotype and Genotype × Temperature interactions were significant for all shoot and root morpho-physiological characteristics evaluated. Higher temperature (HT) significantly affected leaf photosynthetic efficiency, total chlorophyll content, and stomatal conductance. The effect was positive or negative, depending on the genotypes. Tepary accessions showed reduced total chlorophyll content, while common bean genotypes and the interspecific lines were less affected. Tepary accessions also showed reduced stomatal conductance, but increased leaf photosynthetic efficiency under HT. Common bean genotypes increased stomatal conductance and decreased leaf photosynthetic efficiency. High temperature decreased total root length, specific root length and pod biomass compared to ambient conditions, but there was no marked effect on pollen viability of the tested genotypes. The superior adaptation of tepary germplasm accessions to high temperature is attributed to their ability to regulate stomatal opening and photosynthetic efficiency, together with a superior ability to remobilize photosynthates from older leaves to pods during physiological maturity

Highlights

Current climate change estimates predict a rise in global temperatures between 1.4 °C and 3 °C by 2050 and regionspecific variability in precipitation (IPCC, 2007)
There was no difference of production of shoot biomass between high temperature (HT) and ambient temperature (AT) treatments
The average was higher under Higher temperature (HT) (13.1g/plant) compared to the AT (8.6g/plant) mostly because of the superior performance of both tepary accessions and interspecific lines

Summary

Introduction

Current climate change estimates predict a rise in global temperatures between 1.4 °C and 3 °C by 2050 and regionspecific variability in precipitation (IPCC, 2007). These dramatic climate scenarios over the short-term result in worrying predictions of crop yield reduction, especially in abiotic stresssensitive crops such as common bean (Porch et al, 2013). Abiotic and biotic constraints to its production result in an average global yields of 600 kg.ha-1 (Porch et al, 2013). Temperatures > 30 °C during the day or > 20 °C during the night result in yield reduction (Rainey and Griffiths, 2005a). Heat sensitivity is a major limiting factor in the production of common bean, causing reduced yields, lower product quality and restricted geographical adaptation (Rainey and Griffiths, 2005b)

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