I. INTRODUCTION
Rajma is an important legume known as Common bean, French bean, Kidney bean, bush bean, and pole bean. In many developing countries, common bean (Phaseolus vulgaris L.) are being grown for vegetables and pulses in diverse cropping system. The common bean is a self-pollinated species belonging to the Fabaceae family and is the most important sources of the protein (Broughton et al. 2003). A high number of small land holding farmers with low incomes usually adopted to produce the crop. In Nepal, it is cultivated an areas of about 10,529 ha with the productivity 1477 kg/ha and being popular as the cash crop in the Gandaki province, province 5 and Karnali province. It grows as a summer crop in mid/high hills & winter crop in terai/inner terai. The high genetic diversity found in African, Asian and European germplasm has suggested the possibility that those continents could be considered as other centers of genetic diversity for common bean (Ocampo et al. 2005; and Sharma et al. 2014). It is an important legume crop cultivated in a wide range of agro-climatic conditions from Tarai (91m amsl) to high hill (2500m amsl) of Nepal, especially in mountain districts such as Jumla, Humla, Mustang, Rasuwa, Solukhumbu, etc, where mixed landraces with varying morphologies are cultivated. Nepal's hills and mountains are rich in bean diversity, and some landraces have unique characteristics (KC et al 2016, Joshi et al 2017a). In general, common beans grown in high-hill have better taste and are considered more nutritious compared to the beans grown in Terai region of Nepal. More recently, this crop is commonly grown along with kidney bean, fetches good return and have well established market (Neupane et al 2008, Muchui et al 2008, Shrestha et al 2011, Neupane and Vaidya 2002). In these days, area of phaseols bean is in increasing trends due to its good market potential along with good returns. This bean is being popular in Jumla and periphery districts of Karnali province known as Jumla's organic bean gift(Jumla ko Kosheli) in the Nepalgunj and Kathmadu big marts. The main objective of the study was in order to evaluate the quantitative variation with respect to yield and yield contributing traits. In terai region of Nepal, Rajma has been cultivating in winter season. Till date, there is not anyone Rajma variety released/registered for the farmers cultivation. One of the mandated organizations for legumes research, GLRP, Khajura12 has prepared the variety development program in collaboration with NARC satellite stations.
II. MATERIALS AND METHODS
In Coordinated Varietal Trial (CVT); A total of 10 genotypes namely PDR-14, Amber, Utkarsha, Arun-2, BL-63, Kanpur, Chitra NL-1, Pant-1 and Pant-2 were evaluated in 2015 at RARS, Parwanipur and GLRP, Khajura, in 2016 at JRP, Ithari; GLRP, Khajura; ARS, Surkhet and RARS, Parwanipur, same as in 2017 at GLRP, Khajura. Trial was conducted in Randomized Completely Block Design in plot size with three replications. The plant geometry, row-to-row space was maintained as 40 cm and plant to plant 10 cm. Recommended dose of fertilizer 100:60:40 kg NPK/ha was applied, full dose of phosphorus and potash and half dose of nitrogen applied during field preparation and remaining half dose of nitrogen was top dressed after 20-30 days after sowing. During the intervention period, precision agronomic packages were followed and appropriate pesticides and insecticides were applied as per the requirements. Data on agromorphological traits, yield and yield components were collected and data was analyzed using META-R and R-Stat Version 3.2.
III. RESULTS
At Parwanipur, 2015, the results of analysis of variance showed statistically highly significant differences among the genotypes in the agronomic traits days to 50% flowering, days to maturity, plant height, grain yield and 100 seed weight. Genotypes Arun 2(11500 kg/ha) and Utkars (1079 kg/ha) were produced better yield among the tested genotypes in Table 1. Likely in khajura, the results of analysis of variance (Table 2) revealed that genotypes were statistically significant differences in the parameters like plant height, seed per pod and hundred seed weight. Genotype NL1 (563 kg/ha), and Arun-2(542 kg/ha) were produced the highest yield among tested genotypes. NL-1 had a bolder seed (38 g/100 seed). In 2016, at GLRP, Khajura data (Table 3) revealed that the genotypes were highly significant in days to maturity, plant height, and seed weight. Genotype Utkarsh produced the highest yield (2600 kg/ha) followed by, PDR-14 (2471 kg/ha) and Pant-1 (1983 kg/ha). Arun-2 showed the highest seed weight (47 g/100 seed). Same as in 2016, JRP, Ithari data showed that the genotypes were highly significant in days to 50% flowering, days to maturity and plant height and significant in grain yield. Genotype Utkarsh produced the highest yield (1625 kg/ha) followed by, PDR-14 (1412 kg/ha) in Table 4. Data (Table 5) illustrated that genotypes were statistically significant difference in the parameters like days to maturity, plant height, and hundred seed weight. Genotype Amber (3146 kg/ha) produced the highest yield followed by Arun-2(3090 kg/ha) and Utkarsh (2986 kg/ha). Arun-2 had a bolder seed (44 g/100 seed). In
2016, RARS, Parwanipur data analysis of variance showed that the genotypes were highly significant difference in days to flowering, days to maturity, plant height, grain yield and seed weight. Genotype Utkarsh produced the highest yield (1538 kg/ha) followed by, PDR-14 (1369 kg/ha) and Amber (1256 kg/ha). Same as previous Arun-2 had the highest seed weight (52 g/100 seed) in Table 6. Likely in the year of 2017, GLRP, Khajura data analysis of variance revealed that the genotypes were significantly difference (<0.005) in days to 50% flowering, days to maturity, plant height, seed per pod and yield kg/ha. Genotype PDR-14 produced the highest yield (2319 kg/ha) followed by, Utkarsh (1992 kg/ha) and BL-63 (1878 kg/ha) in Table 7. Combined mean analysis of variance showed that genotypes were significantly different in days to maturity, plant height and yield parameters across the locations over the years (2015-2017).
G x E interaction in GGE biplots in figure 1 illustrated that based on both mean and stability the best genotype was Amber then followed by PDR-14. In figure 2 base on concentric ring the ideal genotype was BL-63 however according to figure 3 Ithari was seen the best environment. In figure 4, genotype Amber and Chitra were found ideal and vertex to Khanjra and Surkhet environments, while NL-1 and PDR-14 were ideal for Parwanipur and BL-63, Utkarsh, Kanpur-1 and Arun 2 were found ideal for Ithari environment.
IV. Discussion
Beans are consumed as whole seeds as vegetable or split forms, both as soup or 'daal'. Beans contains healthy proteins, are consumed by all households. Indeed, black bean soup is given to their sick people as an energy supplement. Farmers in Nepal preferred bean landraces that are medium growth habit, early maturing nature, high yielding, good seed size and color and are high demand in the market (Chhetri and Bhatta 2017, Neupane et al 2008). A similar study was done in bean growing area in Malawi to understand the farmer's specifications for variety selection showed that farmers looked on grain color, cooking time, taste, grain size as well as grain brightness to choose the varieties (Chirwa and Phiri 2005). Stoilova et al. (2006) found that out of many accessions studied, some accessions with an erect habit, a shorter period to reach maturity had higher number of pods and seeds per plant as these genotypes escaped unfavorable conditions of high daily temperature and low humidity during the flowering and pod formation periods. In the study, the genotypes had different flowering and pod maturity times even they were planted on the same date. Flowering and pod maturity occurred earliest for all the varieties in the khajura and surkhet than Itahari and Parwanipur site. This flowering data clearly indicated the environment particularly the temperature played an important role in physiological and phenological growth of the varieties included in the study. Similar results of common bean landraces at Mexico showed there were significant differences in the morphological and physiological traits of the plant, pod and grain among different geographic regions which were also associated with different indigenous groups (Chavez-Servia et al 2016). There was effect of genotype by environment interaction on the bean genotypes and yield traits. Some lines showed vertex that mean they were location specific while some lines were highly stable across the locations.
V. CONCLUSION
The combined ANOVA showed that the highly significant differences among the genotypes and locations in the quantitative traits like Days to 50% flower, Days to maturity, Plant height, Hundred seed weight and grain yield. However the effect of GxE interaction was not found in Days to 50% flower, Days to maturity and Grain yield. Overall mean performances in terms of grain yield over the years and across the location showed that the genotype PDR-14 (1862 kg ha-1) produced the highest yield followed by Utkarsh (1698 kg ha-1) and Amber (1666 kg ha-1). Genotype PDR-14 gave 12-35% higher yield among the genotypes and its stability analysis test also indicated that PDR-14 was found a highly stable across the environments and over the years. Variegated red kidney shape seed, white flowers along with dwarf and glabrous leaf pubescence is the distinctness, uniformity and stability (DUS) testing trait of the PDR-14 and recommended for terai/inner terai to high hills.
ACKNOWLEDGEMENTS
The authors are highly acknowledged to the NARC Management team for providing financial support to the research. We are grateful to National Genetic Resources Centre(Gene bank), Khumaltar for supplying the genetic materials of grasspea. We wish to express our sincere gratitude to those subordinated whose efforts and cooperation made this work possible.
