Earliness and developmental characteristics of snap bean (Phaseolus vulgaris L.) genotypes in two growing seasons, pre-winter and winter

Singh BK, Singh PM and Singh B. 2016. Earliness and developmental characteristics of snap bean (Phaseolus vulgaris L.) genotypes in two growing seasons, pre-winter and winter. Vegetable Science 43(1): 44-49.

Abstract                                                                 

The aim of present research on snap bean (Phaseolus vulgaris), which was carried out in the years 2014-2016, to assess the performance of nine varieties/genotypes in two growing seasons of North Indian plains at ICAR-IIVR, Varanasi, UP. In early season (pre-winter), shorter days of first pod-picking (47.5 days), higher picking period index (60.0%), stable and better pod bearing capacity (>21), smaller pod width (<0.85 cm), more pod yield (>110 q/ha), higher genotypic potential realization (92.5%) and greater responsiveness to short day length (4.0-5.5 hr) by genotype VRFBB-91 make it a unique genotype whose genetic potential could be utilized in breeding programmes to widen the genetic variability towards shorter day length, to increase the genotypic adaptability and to harness the potential of earliness in snap bean.

Keywords: Snap bean (Phaseolus vulgaris); earliness; picking period index (PPI); genotypic potential realization (GPR); pod yield; photoperiod.

Introduction

Snap bean (Phaseolus vulgaris L.), a type of common bean (dry bean, shell bean and edible podded bean) whose fresh fleshy tender pods with reduced fibre content in pod-wall, is an important legume vegetable usually used for cooking or canning. It is also known as French bean, garden bean, green bean, string bean, fresh bean or vegetable bean. As the name implies, snap bean breaks easily when the pod is bent, giving off a distinct audible snap sound. The pods (green, yellow and purple in colour) are harvested when they are rapidly growing, fleshy, tender (not tough and stringy), bright in colour, and the seeds are small and underdeveloped (Singh and Singh 2015, Singh et al. 2014, Singh et al. 2011). In India, snap bean is generally grown in the hilly parts of Maharashtra, Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Odisha, Chhatishgarh, Jharkhand, Madhya PradishTamil Nadu, Kerala, Karnataka and West Bengal; Tarai regions of Uttar Pradesh and Bihar; parts of Rajasthan, Haryana and Punjab; and all the parts of North Eastern regions (Singh et al. 2011). The hilly regions of India possess wider genetic variability.

Snap bean is a winter season vegetable in North Indian plains which bears tender pods for a narrow period i.e. mid-January to March first week because it is very sensitive to temperature and photoperiod. Northern Indian plains have problems with cold temperature stress during germination and emergence of the crop, high temperature particularly night-time, occurrence of frost, and short day length during reproductive developments which limit the pod yield of snap bean. High day-time temperature too causes pollen and ovule abortion ultimately affecting pod setting and development. High temperature also enhances stringiness of pods. In order to adapt to high temperature stress, plants employ various physiological adaptive mechanisms viz. earliness, dense canopies, long stay-green, high transpiration rate and reduced photosynthetic rates (Reynolds et al. 1998).

Earliness is the ability of plants to grow and develop rapidly which is determined by how rapid a state of biological and economic ripeness is attained. It has biological as well as economic significance. Biologically, early maturity provides an escape mechanism under incidence of high temperature stress and has been suggested as a good approach for crop breeding for the regions which suffers from terminal high temperature stress (Gur et al. 2010; Mondal et al. 2013); and economically, it provides premium price of product. Temporal meaning of earliness in snap bean could be defined as adaptability of genotype in the preceding growing conditions or the number of days from sowing to the appearance of the first pod. The variation in earliness can be due to an earlier switch from vegetative to reproductive growth or due to faster development of pods. Earliness plays a central role in genotype adaptation to current and new environments; diversifyies the cropping systems; has powerful effect on yield and yield stability; and protects the crops from various abiotic and biotic stresses. As a result, early maturity is an imperative horticultural trait for snap bean breeding. Experiencing the sensitivity of snap bean productivity to temperature and photoperiod requirement, the present study was undertaken to evaluate the performance of nine high yielding varieties/genotypes on plant growth, pod development and yield cultivated under field conditions during two growing seasons in the climes of northern Indian plains at ICAR-IIVR, Varanasi, UP.

References

Acosta-Gallegos JA, Kelly JD and Gepts P (2007) Pre-breeding and genetic diversity in common bean (Phaseolus vulgaris). Crop Sci 47 (Supplement 3): S44–S59.

Gur A, Osorio S, Fridman E, Fernie AR and Zamir D (2010) hi2-1, a QTL which improves harvest index, earliness and alters metabolite accumulation of processing tomatoes. Theor Appl Genet 121: 1587-1599.

Mondal S, Singh RP, Crossa J, Huerta-Espinoa J, Sharma I et al. (2013) Earliness in wheat: A key to adaptation under terminal and continual high temperature stress in South Asia. Field Crops Res 151: 19-26.

Myers JR, Baggett JR (1999) Improvement of snap bean. In: Singh SP (ed) Common bean improvement in the twenty-first century. Kluwer Academic Press, Dordrecht, The Netherlands, pp 289-329.

Reynolds MP, Singh RP, Ibrahim A, Ageeb OAA, Larqué-Saavedra A, Quick JS (1998) Evaluating physiological traits to complement empirical selection for wheat in warm environments. Euphytica 100: 84-95.

Rosales-Serna R, Kohashi-Shibata J, Acosta-Gallegos JA, Trejo-López C, Ortiz-Cereceres J and Kelly JD (2002) Yield and phenological adjustment in four drought-stressed common bean cultivars. Ann Rep Bean Improv Coop 45: 198-199.

Singh BK and Singh B (2015) Breeding perspectives of snap bean (Phaseolus vulgaris L.). Veg Sci 42 (1): 1-17.

Singh BK, Deka BC and Ramakrishna Y (2014) Genetic variability, heritability and interrelationships in pole-type French bean (Phaseolus vulgaris L.). Proc National Acad Sciences, India Sect B: Biolog Sciences 84 (3): 587-592.

Singh BK, Pathak KA, Ramakrishna Y, Verma VK and Deka BC (2011) Purple-podded French bean with high antioxidant content. ICAR News: A Sci Tech Newsl 17 (3): 9.

Singh BK, Pathak KA, Verma AK, Verma VK and Deka BC (2011) Effects of vermicompost, fertilizer and mulch on plant growth, nodulation and pod yield of French bean (Phaseolus vulgaris L.). Vegetable Crops Res Bull 74: 153-165.