MSc

Experiments to assess the impact of foliar application of secondary nutrients, micronutrients growth promoters on growth, fruit and seed yield of okra variety Arka Anamika, and the influence of storage environment on quality and longevity of the seed thus produced were conducted at College of Horticulture, Vellanikkara, Thrissur, during 2016-2018. The field experiment was laid out in a Randomized Block Design (RBD) with 18 treatments. The dosage of micronutrients and secondary nutrients to be applied as foliar nutrition in the experimental plot were fixed based on the soil test data. As the soil of the experimental plot was found to be deficient in secondary nutrients viz., magnesium and sulphur as well as in micronutrients; zinc and boron, the treatments were designed to augment the required secondary and nutrients through foliar application. Foliar application of 0.75% ZnO, 1% MgO, 0.2% Pseudomonas Fluorescens (Pf), 0.2% Salicylic acid (SA), 0.5% Sampoorna KAU vegetable multimix (SVM), 0.1% H3BO3, 0.5% Sulphur (s), 0.75%ZnSO4 and water (control:C), was done either once at 25 days after sowing (T1: 0.75%ZnO-1, T3:1% MgO-1, T5:0.2% pf-I, T7:0.2%SA-I, I,T9:0.5% SVM-I,T11:0.1%H3BO3-I, T13:0.5% 0.5%S-I, T 158:0.75% ZnSO-I and T 17:C-I) or twice at 25 DAS and 45 DAS (T2:0.75% ZnO-II, T4:1% MgO-II, T6:0.2%PF-II, T8:0.2%SA=II, T10:0.5% SVM-II,T12 :0.1%H3BO3II,T14:0.5%SII,T16:0.75%ZnSO4-II and T18:C-II,during the cropping period and observation on growth and yield parameters were recorded at appropriate stages.
Results revealed the existence of significant differences in most vegetative and reproductive traits in okra, following foliar application of various nutrients and growth promoters. However, no significant difference was observed with respect to plant height at 30 days after sowing (DAS) and 60 DAS, days to flowering pollen viability (%), seeds per pod, shrivelled seeds per pod (%) and seed yield per pod (g).
Considering the impact of various nutrients and growth regulators, it may be concluded that foliar application of micronutreint mixture (0.5% Sampoorna KAU vegetable multimix) or 0.75% ZnSOS4 or 0.1% H3BO3 twice during the crop growth was advantageous. Foliar application of micronutrient mixture (0.5% Sampoorana KAU vegetable multimix) twice, exerted high positive influence on the vegetative growth and reproductive traits in okra seed crop except per cent of hard seeds and test weight. The treatment had registered the highest fruits per plant and the least per cent of flower shedding. Two-time foliar application of 0.5% Sampoorna KAU vegetable multimix was more advantageous than its one-time application. Although high in saleable seed (%) as well as test weight and low in hard seed per cent, the plant stature at both 45 DAS and 75 Das, chlorophyll content in leaves, number of branches and fruits per plant, fruit length and seed density were comparatively low in one-time application of 0.5% Sampoorna KAU vegetable multimix. The flower shedding was also application of comparatively high in one time application of vegetable multimix. One- Time application of 0.5% Sampoorna KAU vegetable multimix was found next best to two-time application of 0.5% Smpoorna KAU vegetable multimix or 0.75% ZnSO4 and 0.1% H3BO3.
Foliar application of 0.75% ZnSO4 twice and 0.1% H3BO3 twice were comparable to each other. The treatments were on par with respect to plant height at 75 DAS, chlorophyll content in the leaf, flower shedding (%), number of fruits per plant, fruit lengh, per cent hard seeds and saleable seeds, test weight of seed and seed density. Application of 0.75% ZnSO4 twice exhibited a highly beneficial effect on reproductive traits of seed crop. The highest saleable seed per cent was registered in this treatment. Low percent of flower shedding and hard seeds as well as high number of fruits per plant and fruit length were observed in this treatment. In spite of the low plant stature at both 45 and 75 DAS and chlorophyll content, all the reproductive traits viz., number of fruits per plant, fruit length, saleable seed per pod (%)test weight and seed density in treatment 0.1% H3BO3twice i.e., at 25 DAs and 45 DAS was of high magnitude. In addtiion, the treatment had regidstered lower percent of flower shedding and hard seed. High test weight coupled with high seed density indicates good grain filling.
Administering plant growth promoting rhizobacterium Pseudomonas fluorescens twice via foliar sprays can also be recommended to reduce per cent of hard seeds and obtain high saleable seed per pod (%). However, it did not improve the plant stature at early stages (45 DAS) and number of branches, chlorophyll content in leaves and seed test weight or lower the occurrence of hard seeds per pod (%).
Seed storge experiments were laid out following a Completely Randomized Desigh (CRD) with eighteen treatments (T1 to T18) and three replications (R1 to R 3) under three storage conditions. The study was done using the seeds extracted from the pods harvested at physiological maturity from each of the 18 treatments in Experiment I. Seeds were stored under three storage conditions viz., shelled seeds under refrigerated storage (S1), shelled seeds under ambient storage (S2) and unshelled pods under ambient storage (S3).
The foliar application of nutrients and growth promoters in okra significantly influenced the seed the elemental composition of seeds except for iron and sulphur content. It was observed that the foliar application of boron, zinc, and magnesium increased the content of respective elements in the seed. Sampoorna KAU vegetable multimix (0.5%) was beneficial in increasing the boron, manganese, copper calcium and magnesium content of seed. Next to the micronutrient mixture, it was also evident that the content of boron, manganese magnesium and calcium content of seed was enhanced through spray of salicylic acid.
Before storage, the foliar application of nutrients and growth promoters was found to exert a significant influence on the seed quality indices (Germination per cent, seedling vigour index I and seedling vigour index II). Results of storage studies indicated that, as storage period increased the seed quality decreased irrespective of the storage environment. The rate of seed deterioration was found to be maximum when the seeds were stored in unshelled pods. Hence, it can be summarized that compared to storing seeds with i unshelled pods, ambient storage and cold storage conditions are beneficial in prolonging longevity and maintaining higher seed quality parameters during storage.
Although, the results point out that foliar application 0.5% Sampoorna KAU vegetable multimix twice positively influenced seed quality during storage, a conclusive evidence as to the best foliar treatment that positively impacts seed quality parameters can be drawn only from the study of seed quality parameters over prolonged storage (>6 Months). Further evaluation of seed quality under ambient and refrigerated storage environment over a longer storage period would also help delineate the impact of these treatments as well as environment on seed longevity and quality during prolonged storage.