Evaluation of pre-sowing interventions on seed quality, storage and field performance of Okra (Abelmoschus esculentus L. Moench)

Abstract

The research work entitled ‘Evaluation of pre sowing interventions on seed quality, storage, and field performance of okra (Abelmoschus esculentus L. Moench)’, was conducted as two experiments in the Department of Seed Science and Technology, College of Agriculture, Vellanikkara, during 2022-2023. Five months old seeds (variety – Arka Anamika) were subjected to fourteen pre sowing treatments namely, T1-Control, T2-Hydration-Dehydration (12 hours), T3-PEG 6000-13.5% (-0.25Mpa) 6 hours, T4-KNO32%(6hours), T5-sandmatric (60% WHC-3hours), T6-Trichoderma viride 4g/kg of seed, T7-Pseudomonas fluorescens 10g/kg of seed, T8-Hydration-Dehydration (24 hours), T9-PEG 6000-13.5% (-0.25Mpa) 12 hours T10-KNO3 2% (12 hours) T11-sand matrix (60% WHC -6 hours), T12-T.viride 4g/kg+P indica 5x105 spores Ml-1) 10 ml/kg were carried out. The initial seed quality parameters such as germination per cent -94%, vigour index I-1474, vigour index II-2.73, and moisture percent – 7.2 respectively, were assessed before storage and field experiments. In experiment I, the seeds were subjected to eleven of the fourteen presowing treatments mentioned earlier with three replications. These were then dried to less than eight percent moisture, packed in 700g polythene bags and stored under ambient conditions. The observations for all quality parameters were recorded immediately after the treatments and at monthly intervals for six months of storage period. The treatments displayed significant variations across all the investigated seed quality parameters. Among the treatments, treatment T9(PEG 6000-13.5% (-0.25Mpa) 12 hours) recorded the best seed qualities in all months of storage, followed by treatment T4 (KNO3 2% - 6 hours). The storage study clearly demonstrated that the quality of seeds consistently diminished with an extended storage period, regardless of the treatments applied. In the case of germination, all treatments, including control maintained the Indian Minimum Seed Certification Standard (IMSCS) of 65 percent up to the sixth month of storage. Seed quality parameters such as germination percent, vigour index I, vigour index II, seedling length, seedling dry weight and seedling fresh weight decreased with the advancement of the storage period. The electrical conductivity of seed leachate, mean germination time, time taken for 50% germination, seed moisture percent and seed microflora percent were found to be increasing over the period of storage. In experiment II, the seeds were subjected to thirteen treatments and control mentioned earlier. Among these, seven best treatments along with control were selected based on germination percentage and vigor index for the field experiment. The experiment was laid out in RBD (Randomized Block Design), with three replications. Maximum germination percentage was obtained in T4 (PEG 6000-13.5% (-0.25MPa) 6 hours -99.66) and it was on par with T10(Trichoderma viride at 4g/kg of seed), T5(PEG 6000-13.5% (-MPa) 12 hours), T6 (KNO3 2% (6 hours), T3 (hydration-dehydration (24 hours), T9 (sandmatric (60% WHC – 6 hours) and T11 (P. fluorescens at 10g/kg of seed). The results indicated that the pre sowing treatments showed significant differences for all the characters studied. In terms of growth characters, T3 (PEG 6000-13.5% (-0.25MPa) 6 hours) had the maximum number of branches per plant. T8 also had the least number of days to first and 50% flowering. All the fruit characters such as fruits per plant, fruit length (cm), fruit weight (g) at maturity and fruit yield (t/ha) were recorded maximum in treatment T8(P. fluorescens at 10g/kg of seed) which was followed by T7 (Trichoderma viride at 4g/kg of seed). Similarly, all the seed yield characters such as, sees per fruit, seed yield per plant (g) and 100 seed weight(g) were also highest in T8 followed by T7. This underscores the significant impact of biocontrol agents such as P. fluorescens and T. viride on both fruit yield and seed yield characters. The ranking of traits in Experiment II aimed to identify the most effective treatments for enhancing the field performance of okra. Based on the total scores, T8(P. fluorescens at 10 g/kg of seed) emerged as the best treatment followed by T7(T. viride at 4g/kg of seed).

In conclusion, treatments T9(PEG 6000-13.5% (-0.25Mpa) 12 hours) and T4 (KNO3 2% (6 hours) were found to be maintaining the seed quality. Additionally, treatments involving P. fluorescens and T. viride proved to be valuable for enhancing fruit yield and seed yield in okra variety Arka Anamika.