Seed treatment in cowpea (vigna unguiculata L.) for seed quality enhancement using botanicals

Abstract

The present investigation entitled “Seed treatment in cowpea (Vigna unguiculata L.) for seed quality enhancement using botanicals” was carried out at the Regional Agricultural Research Station (RARS) Pattambi, Kerala. The study aimed to assess the effect of seed hardening with organic leaf extracts on filed performance, seedling quality parameters and nutritional attributes of cowpea during the storage period. This study consists of three experiments (Experiment -1) Effect of seed hardening with organic leaf extracts on field performance of cowpea. It was evaluated by using randomized block design (RBD) with nine treatments including control (5% leaf extracts of Calotropis, Papaya, Pongamia, Castor, Moringa, Vitex, Neem, Tulsi and Control) and 3 replications. Seeds were soaked in 5% leaf extracts for four hours and then shade dried to their original moisture content. Crop raised as per POP recommendation of KAU (2016). Observations were recorded on growth and yield parameters during crop growth stages. The results revealed that the performance of seeds treated with organic leaf extracts was better compared to the control. A significant effect was observed in seeds treated with Pongamia leaf extract had given the highest values for plant height (145.07 cm), number of branches per plant (10.27), number of clusters per plant (7.53), number of pods per plant (12.13), seed yield per plot (353.62 g), dry matter production at harvest (56.95 g), and nodule count per plant (17.78). Seeds treated with Calotropis leaf extract had given the highest values for, pod length (17.18 cm) and pod weight (10.63g). Similarly, neem leaf extract had given the highest values for pod girth (2.2 cm) and 100 seed weight (12.88 g). (Experiment-2) The effect of seed treatment with organic leaf extracts on the seedling quality parameters of cowpea was evaluated in a completely randomized design with three replications. Seed treatment was done as in the previous experiment and then shade-dried the seeds for two days, bringing the moisture content to less than 8 %, and packed in a 700-gauge polythene bag kept for storage in ambient conditions.

Observations were recorded on seedling quality parameters at the start of the storage, 45 DAS and 3 months after storage. It was observed that seeds treated with organic leaf extracts had better performance compared to control. A significant effect was observed in seeds treated with Pongamia leaf extract had given the highest values for emergence per cent (61.67 %), root length (10.33 cm), seedling dry weight (0.048 g), low electrical conductivity of seed leachate (0.467 dSm -1), emergence index (21.38) and seedling vigour index-II (3.03). Seeds treated with Calotropis leaf extract had given the highest values for germination per cent (63.67 %), low pulse beetle infestation (16.33 %), germination index (324), mean germination time (3.87 days), time taken for 50 % germination (3.34 days) and seedling vigour index-I (2259) by the end of the storage period. Seeds treated with Papaya leaf extract had given the highest values for shoot length (25.65 cm). Similarly, low seed microflora per cent (19.05%), was recorded in seeds treated with neem leaf extract by the end of the storage period. (Experiment-3) The effect of seed treatment with organic leaf extracts on the nutritional attributes of cowpea. Experiments 3 was carried out simultaneously with Experiment 2 by using the same seeds kept for storage in the Experiment 2. Observations were recorded on nutritional attributes which include crude protein, crude fat, crude fibre, vitamin C, calcium content, iron content, ash content, carbohydrate content and phytic acid content at the start of storage, 45 DAS and 90 DAS .

A significant effect was observed in seeds treated with Pongamia leaf extract, which had given the highest values for calcium content (48.03 mg/100 g), iron content (2.42 mg/100 g), ash content (4.07 %) and carbohydrate content (51.03 %) by the end of the storage period. Among all the treatments, seeds treated with Pongamia leaf extracts had given the better performance compared to control in field performance as well as improvement in seedling quality parameters and preserving the nutritional attributes of cowpea during the storage period.