Effect of Different Dates of Sowing on Growth, Yield Attributes and Yield of Various Cultivars of Kharif Blackgram (Vigna mungo L.) under Amritsar Conditions

Pulses have great importance in Indian agriculture as they are rich source of protein (17 to 25%) as compared to cereals (6 to 10%) their ability to fix atmospheric nitrogen and maintain soil fertility. Among pulses, blackgram is one of most important crop. Blackgram has originated from Indian sub-continent (De Candolle, 1986) where it has been cultivated from ancient times and standout amongst most expensive pulse crop in India. It provides a major share of the protein requirement of the vegetarian population of the country (Shobanadevi et al., 2021). It is widely used in Punjabi cuisine and frequently alluded to as “Maah di Daal” in local language. In Punjab, Blackgram was grown on 2.0 thousand ha area with total production of 1.1 thousand ton during 2018-19 (Anonymous, 2020). Amritsar being an integral blackgram producing district in Punjab contributing 9.1% to total production and standing at 4^th position (Anonymous, 2019). Blackgram is highly sensitive to abiotic stresses. Being observed, the productivity of blackgram is low in India as well as in Punjab due to lack of knowledge regarding various agronomic implementations, among them, time of sowing and selection of suitable cultivar are one of the major limiting factors in production, especially during kharif season. The optimum time of sowing ensures the complete harmony between the vegetative and reproductive phases on one hand and climatic rhythm on the other and helps in realizing the potential yield. Varietal adaptation is the important factor which is generally associated with low productivity of this crop. The new improved cultivars have high yield potential, resistant to disease and insect pests as compared to old and degenerated cultivars. Keeping this in  view the present investigation was initiated to find out a suitable date of sowing and cultivar for higher kharif blackgram production under the agro-climatic conditions of Amritsar.

A field experiment was undertaken at Student’s Research Farm, Department of Agriculture, Khalsa College, Amritsar during kharif season 2019 to study the effect of different dates of sowing on growth, yield attributes and yield of various cultivars of kharif blackgram (Vigna mungo L.). The soil of experimental site described as sandy loam in texture, normal in pH (7.9), medium in organic carbon (0.66 %), low in nitrogen (216 kg/ha), medium in phosphorus (12.5 kg/ha) and medium in potassium (126 kg/ha). The experiment was laid in split plot design with four replication where as main plots were assigned to four dates of sowing viz. 8^th July, 18^th July, 28^th July and 8^th August and sub-plots to three cultivars i.e. Mash 114, Mash 338 and KUG 479. Recommended uniform dose of N and P₂O₅ was 5:10 kg/acre. The entire quantity of these fertilizers was applied as basal at the time of sowing. The seed @ 20 kg/ha were dibbled at 30 × 10 cm² spacing on raised beds. Before sowing seeds were treated with Rhizobium culture @ 250 g/acre to ensure nodulation. The weeds were managed by pre-emergence application of Stomp 30 EC (Pendimethalin) herbicide applied after sowing on the same day in evening. Hand weeding was carried out twice at 30 and 45 DAS. Crop was harvested with sickle and threshed manually. The growth parameters were recorded at 30, 45 and 60 DAS whereas the yield attributing and yield parameters were recorded at harvest. The collected data were subjected to statistical analysis with CPCS-1 software developed by Punjab Agricultural University, Ludhiana.

Effect of sowing dates
 
The results (Table 1) revealed that there is no significant effect on days taken to emergence due to dates of sowing. The plants under 8^th July sowing took higher number of days to achieve 50% flowering as compared to the other dates. Delay in sowing resulted in early flowering. Singh and Kumar (2014) also reported reduction in days taken to 50% flower with delayed sowing.  Plant height, an index of growth, was found markedly influenced by planting dates.  Significantly higher plant height was recorded in 8^th July sown crop at 30, 45 and 60 DAS as compared to other three sowing dates. It was mainly due to early sowing dates had longer growing period. These findings are in line with earlier finding by Singh et al., (2011). Similarly, 8^th July sown crop produced maximum leaf area index from 30 to 60 DAS it was significantly superior over all other sowing dates. Crop sown on 8^th July showed significantly higher dry matter accumulation at 30, 45 and 60 DAS than other 28^th July and 8^th August sowing dates but at par with 18^th July sown crop. The highest DMA in early sown crop might be due to availability of more time for vegetative growth (Singh and Singh, 2015). The higher values of LAI in early sown crop resulted in increased production of photosynthates contributing to higher total dry matter production. These results agreed with the findings of Yadahalli et al., (2006) and Dwivedi et al., (2018). The variation in number of nodules by different sowing dates was non-significant at 30 DAS whereas at 45 and 60 DAS it was significant. 8^th July sown recorded significantly higher number of nodules per plant as compared to 18^th July, 28^th July and 8^th August sowings. Nodulation was reduced with delayed sowing.
 

      
Yield data (Table 2) revealed that 8^th July sown crop produced significantly maximum number of pods/plant, seeds/pod, pod length, seed weight/plant which was significantly higher than 28^th July and 8^th August and statistically at par with 18^th July sown crop. All these yield attributes were decreased notably with delay in sowing up to 8^th August sowing date. The rapid increase in yield attributes was due to more vigorous growth in early planting, resulting in more translocation of photosynthates from leaves to the reproductive parts. Similar results were obtained by Patidar and Singh (2018) and Jha et al., (2015). Crop sown on 8^th July recorded maximum seed yield (10.27 q/ha) and straw yield (26.52 q/ha) which was significantly higher than the other sowing dates. Seed yield was progressively declined with delay in sowing mainly due to reduction in number of pods/plant, seeds/pod and seed weight/plant. Higher grain yield of 8^th July sown blackgram as compare to remaining dates was probably due to favourable source-sink relationship together with favourable weather conditions around 8th July which caused better growth of plant. Similar results were also advocated by Gangwar et al., (2012). The harvest index and 1000-seed weight was found to be non-significant for different dates of sowing. Similar trend was observed by Singh and Kumar (2014).
 

 
Effect of varieties
 
Data revealed (Table 1) that there is no significant effect on days taken to emergence due to various cultivars. But cultivars differed significantly with regard to number of days taken to reach 50% flowering. The cultivar Mash 114 took considerably less number of days to reach 50% flowering than other cultivars. This could be attributed to genetic variations existing among blackgram cultivars as also reported by Meena and Ram (2016). Mash 114 attained significantly higher plant height at 30, 45 and 60 DAS as compared to Mash 338 and KUG 479. It might be due to genetic character of Mash 114. Singh et al., (2011) also found variation in plant height among various cultivars. The cultivar Mash 114 was found significantly superior in LAI at 30 to 60 DAS over Mash 338 and KUG 479 cultivars. Dry matter accumulation per plant was markedly influenced due to cultivars at different crop growth stages. The cultivar Mash 114 was found significantly superior at 30, 45, 60 DAS and over the other cultivars. This might be due to higher biomass potential and high nutrient absorption capacity of the cultivar. These observations are confirmed by the finding of Kumar et al., (2018). Mash 114 recorded significantly higher root nodules per plant at 45 and 60 DAS than Mash 338 and KUG 479. This might be due to more number of fibrous roots and larger tap root system of Mash 114 than the other varieties. Similar genotypic differences were observed by Ibrahimi et al., (2017).
      
The performance of Mash 114 as regard to yield attributing characters viz. number of pods/plant, seeds/pod and seed weight/plant was significantly superior over the two varieties (Table 2). The probable reason for this may be improved photosynthetic activity due to increased source capacity and efficient translocation of photosynthates to the seed (Jadhav et al., 2014). The blackgram cultivar Mash 114 recorded higher seed yield (10.19 q/ha) and straw yield (26.47q/ha) which was significantly superior over Mash 338 and KUG 479. This increase in seed yield (Fig 1) of Mash 114 cultivar might be due to the higher production efficiency that has been reflected through improvement in different yield attributing characters. Similar findings were reported by Sharma (2015).
 

On the basis of investigation carried out under agro-climatic conditions of the results showed that for higher production and productivity of kharif blackgram. The crop sown in early July with cultivar Mash 114 gave higher seed yield and B:C ratio to enhance the area under pulses in Amritsar region.