Rajmash is also known as haricot bean, salad bean, runner bean and common bean. In India both bushy and trailing type Rajmash is found. It is native of southern Mexico and central America. Among food legumes the French bean is the third most important worldwide famous crop superseded by soybean and peanut. In India, it is mainly grown in Maharashtra, Himachal Pradesh, Punjab, Haryana, Uttar Pradesh, Bihar, Tamil Nadu and Jammu and Kasmir. In Maharashtra, it is mainly grown in Satara, Pune, Sangli and Kolhapur districts. Rajmash also possesses some medicinal properties which are useful in controlling diabetics and certain cardiac problems and it is a good natural cure for bladder burn. There is need to organize strong and efficient breeding programme to develop high yielding and good quality varieties of French bean which comes under pulse crops. At present development of strict ideotype as identified by the physiologists and adaptability to a wide range of environment is a major criterion for selection in French bean (Evans 1976). The ability of individual populations or species to change in form or function in such a way to survive better under given environmental conditions is termed as adaptability (Allard 1960). Some genotypes do well only under certain sets of environmental conditions such as poor or rich environments. The stability depends upon adaptability of the genotype. Stability in the yield and its components is therefore one of the most desirable characters for the adaptability of all genotypes. The low yield of this crop in India is mainly attributed to the lack of stable high yielders and environmental variations. Genotype cannot therefore be selected based on yield alone but a method that combines yield and stability across a geographical area would be beneficial to the farmers.

Sowing time is a major non-monetary input affecting growth and grain yield (Sadhukhan et al 2008, Patange et al 2011, Kalita et al 2016) and is considered an important factor to explore the maximum yield. Genotypes may also differ in the productivity (Patange et al 2011, Kalita et al 2016). The proper growth of a genotype is determined by its growing environment. Different genotypes may perform differently under diverse environments. Therefore performance of genotypes under different sowing windows is needed to be tested. Present investigations were therefore planned to identify adaptable genotypes suitable for kharif season.

The experiment comprised ten varieties of Rajmash (Phaseolus vulgaris L) evaluated in randomized block design with three replications over four environments in the field. Each genotype was planted in four rows of 30 cm x 10 cm spacing. The field experiment was conducted on normal fertile soil. The crop was grown during kharif 2015 season under four different sowing dates (environments) viz E₁: 20 June 2015, E₂: 10 July 2015, E₃: 30 July 2015 and E₄: 20 August 2015 at the instructional farm of the College of Agriculture, Pune, Maharashtra. The land was prepared by ploughing followed by two cross harrowings. The basal dose of 60 kg N and 80 kg P₂O₅ per hectare was applied in all four sowings. The observations were recorded on number of days taken to 50 per cent flowering, number of days to maturity, plant height, plant spread, number of primary branches per plant and seed yield per plant. The data were collected on five randomly selected plants per replication in each plot. Mean sum of squares for individual environments and testing the genotype differences were calculated as suggested by Panse and Sukhatme (1985).

The mean sum of squares due to treatments under each environment for all characters studied in E1, E₂, E₃ and E₄ are presented in Table 1. The differences due to treatments were highly significant for all characters except for number of primary branches per plant (E4).

The data on the effect of different environments on various yield attributing and yield characters are given in Table 2.

Genotypes GRB-803 (32.00), Phule Suyash (32.00) and and Vaghya (33.00) took minimum number of days to 50 per cent flowering under E₁ (20 June 2015); GRB-702 (25.66 days) under E₂ (10 July 2015); GRB-803 (31.46) and Phule Suyash (31.20) under E₃ (30 July 2015) and GRB-701 (30.33), GRB-803 (30.53) and Phule Suyash (30.73) under E₄ (20 August 2015). The number of days to 50 per cent flowering decreased with the delay in sowing. Singh et al (2005) reported that heat units consumed by chickpea for 50 per cent flowering were higher in first sowing that is 15 November 2005. The performance of GRB-803 and Phule Suyash was better among all the genotypes for the character number of days to 50 per cent flowering.

In case of number of days to maturity, GRB-803, Phule Suyash and Varun (check) took minimum days (72.00 each) under E₁ (20 June 2015); GRB-803 (71.60 days) and Varun (check) (71.40 days) under E₂ (10 July 2015); GRB-804 (70.80), Phule Suyash (70.80) and Varun (check) (70.26) under E₃ (30 July 2015) and Varun (check) (69.13) under E₄ (20 August 2015). The number of days to maturity decreased with the delay in sowing. The performance of GRB-803 and Phule Suyash was at par with Varun (check) for days to maturity.

In case of plant height, GRB-902 (58.13 cm) and Varun (check) (57.20 cm) under E₁ (20 June 2015); GRB-902 (57.86 cm) and Varun (check) (56.33 cm) under E₂ (10 July 2015); GRB-702 (54.53 cm), GRB-902 (54.60 cm) and Varun (check) (53.20 cm) under E₃ (30 July 2015) and GRB-702 (52.86 cm), GRB-902 (52.13 cm) and Vaghya (51.80 cm) under E₄ (20 August 2015) resulted in maximum plant height as compared to other genotypes. The performance of GRB-902 and GRB-702 was found better for the character plant height. Singh et al (2020) reported that the plant height of Rajmash was significantly affected by different sowing dates at Ludhiana, Ballowal Saunkhri and Gurdaspur in Punjab.

For plant spread, GRB-902 proved significantly superior over all other genotypes with 16.86 and 16.06 cm spread under E₁ (20 June 2015) and E₂ (10 July 2015) respectively whereas in case of E₃ (30 July 2015), GRB-902 resulted in maximum plant spread (15.06 cm) which was at par with Varun (check) (14.40 cm) and in case of E₄ (20 August 2015), GRB-902 again resulted in maximum plant spread (14.00 cm) which was at par with GRB-701 (13.06 cm), GRB-702 (13.60 cm) and Varun (check) (13.73 cm). The plant spread decreased with the delay in sowing.

Number of primary branches under E₂ (10 July 2015) were lower in GRB-804 (2.40) followed by Vaghya (2.66) whereas all other genotypes were having more number of primary branches and were at par with one another. Under E₄ (20 August 2015), GRB-902 proved better with 2.73 number of primary branches which was significantly higher than all other genotypes. However the genotypes did not differ among themselves for this character under E₁ (20 June 2015) and E₃ (30 July 2015).

GRB-702 (22.90 g) and GRB-902 (23.53 g) gave maximum seed yield per plant under E₁ (20 June 2015). Under E₂ (10 July 2015), GRB-701 (20.10 g), GRB-702 (20.03 g), GRB-902 (20.80 g) and Varun (check) (19.60 g) resulted in maximum seed yield per plant and were at par with one another. The trend was almost parallel to E₂ (10 July 2015) in case of E₃ (30 July 2015) and E₄ (20 August 2015). GRB-701, GRB-702 and GRB-902 performed better than all other genotypes which were at par with Varun (check) for the trait seed yield per plant. The yield decreased with the delay in sowing. Choudhary and Haque (2010) and Pillai et al (2010) reported significant differences among genotypes in different environments and seasons. Ujjammanavar et al (2006) also reported that the yield of Rajmash was reduced significantly when the sowing was delayed. In Bangladesh, January sowing gave the highest grain yield of Rajmash whereas the crop sown in February failed to produce any grain (Begum et al 2003).

In overall it can be concluded that GRB-803 and Phule Suyash (number of days to 50% flowering), GRB-803 and Phule Suyash (number of days to maturity), GRB-702 and GRB-902 (plant height), GRB-902 (plant spread), GRB-902 (number of primary branches/plant) and GRB-701, GRB-702 and GRB-902 (seed yield/plant) were the better genotypes of Rajmash.

Significant at 5% LoS,

Significant at 5% LoS

E₁: 20 June 2015, E₂: 10 July 2015, E₃: 30 July 2015, E₄: 20 August 2015

References