MSc

The study entitled “Seed invigouration for yield enhancement in grain cowpea (Vigna unguiculata L.Walp)” was undertaken during 2017-2019, at College of Agriculture, Vellayani, Thiruvananthapuram, Kerala, with the objectives to assess the effect of seed invigouration with zinc sulphate and borax on grain cowpea and to evaluate its effect along with Trichoderma viride on growth and yield of the crop.

Research work comprised of one pot culture experiment and a field experiment which were carried out at Coconut Research Station, Balaramapuram. The variety used for the study was Bhagyalakshmy. Pot culture experiment was laid out in completely randomized block design with thirteen treatments and three replications during Rabi 2018. The treatments comprised of six pelleting treatments viz., T1 and T2 (seeds pelleting with ZnSO4 100 and 200 mg kg-1 seed), T3 andT4 (seeds pelleting with borax 50 and 100 mg kg-1 seed) , T5 and T6 (ZnSO4 100 mg + borax 50 mg kg-1 seed and ZnSO4 200 mg + borax 100 mg kg-1 seed) and six priming treatments viz., T7 and T8 (seed priming with ZnSO4 0.025 and 0.05 per cent for 4 h) , T9 and T10 (seed priming with borax 0.01 per cent and 0.02 per cent for 4 h), T11 and T12 (seed priming with ZnSO4 0.025 + borax 0.01 per cent for 4 h and ZnSO4 0.05 + borax 0.02 per cent for 4 h) and a control (T13).

Seed pelleting with borax 50 and 100 mg kg-1 seed and seed priming with ZnSO4 0.025 and 0.05 per cent recorded higher germination percentage, mean daily germination, speed of germination, germination index, germination rate index, co-efficient of rate of germination, seedling vigour index I and II and lesser mean germination time and time taken for 50 per cent germination. Hence, seed pelleting with borax 50 and 100 mg kg-1 seed and seed priming with ZnSO4 0.025 and 0.05 per cent which showed fast, uniform synchronous emergence with high vigour index were selected as the two best seed pelleting and priming treatments for field experimentation.

The field experiment was laid out in randomized block design with nine treatments and three replications during Rabi 2018. The treatments comprised of seed pelleting with borax 50 and 100 mg kg-1 seed; seed priming with ZnSO4 0.025 and 0.05 per cent for 4h; seed pelleting with borax 50 and 100 mg kg-1 seed + Trichoderma viride seed treatment 10 g kg-1 seed and seed priming with ZnSO4 0.025 and 0.05 per cent for 4h + Trichoderma viride seed treatment 10 g kg-1 seed and a control.

Results revealed that seed invigouration had significant effect on growth parameters, physiological parameters, yield attributes, yield, protein content, nutrient uptake, post-harvest nutrient availability, disease incidence and economics.

Seed priming with ZnSO4 0.05 per cent for 4h and seed priming with ZnSO4 0.05 per cent for 4h + Trichoderma viride seed treatment 10 g kg-1 seed recorded higher number of branches per plant and green leaves per plant. However, seed priming with ZnSO4 0.05 per cent for 4h recorded the highest dry matter production at harvest.
Leaf area index and total chlorophyll content were found to be significantly higher in seeds primed in ZnSO4 0.025 and 0.05 per cent for 4h at both 30 and 60 days after sowing (DAS). During 30 to 60 DAS, crop growth rate (CGR) and relative growth rate (RGR) were the highest in seeds pelleted with borax 50 mg kg-1 seeds and during 60 DAS to harvest, seeds primed in ZnSO4 0.05 per cent for 4h registered the highest CGR and RGR.

Total number of nodules and effective nodules per plant were found to be significantly higher in seeds pelleted with 50 and 100 mg kg-1 seed. However, the fresh and dry weight of nodules were the highest in seeds primed in ZnSO4 0.05 per cent for 4h.

Pods per plant, pod weight per plant, pod length, pod girth, seed yield per plant, seed yield ha-1 and harvest index were the highest in seeds primed in ZnSO4 0.05 per cent for 4h. Among the seed pelleting treatments, seeds pelleted with borax 50 and 100 mg kg-1 seed recorded higher seed yield. Seed priming with ZnSO4 either with 0.025 or 0.05 per cent or pelleting with borax either with 50 or 100 mg kg-1 seed recorded higher seed yield than seed priming with ZnSO4 or pelleting with borax combined with Trichoderma viride seed treatment 10 g kg-1 seed.

Total NPK uptake by crop was the highest in seed priming with ZnSO4 0.05 per cent for 4h. However, seed priming with ZnSO4 0.05 per cent for 4h + Trichoderma viride seed treatment 10 g kg-1 seed recorded the highest Zn uptake and seeds pelleted with borax 100 mg kg-1 seed recorded the highest B uptake.

Results on nutrient status of soil after the experiment revealed that seeds primed in ZnSO4 0.05 per cent for 4h recorded the highest organic carbon content and available N status. Seeds pelleted with borax 100 mg kg-1 seed recorded the highest available P and seeds primed in ZnSO4 0.05 per cent + Trichoderma viride seed treatment 10 g kg-1 seed recorded the highest available K status. Seed priming with ZnSO4 0.05 per cent for 4h recorded the highest available soil Zn status, whereas, seed pelleting with borax 100 mg kg-1 seed recorded the highest available soil B status.

Seed invigouration treatments recorded significantly higher crude protein content than control and the highest crude protein content was recorded in seed priming with ZnSO4 0.05 per cent for 4h.

Seed invigouration treatments recorded lower incidence of anthracnose disease than the control and among the treatments, the lowest incidence was recorded in seed priming with ZnSO4 0.05 per cent for 4h.

The net returns and benefit cost ratio were the highest in seeds primed in ZnSO4 0.05 per cent for 4h.

Considering the yield attributes, yield, disease incidence, and economics seed priming with ZnSO4 0.05 per cent for 4h along with recommended dose of FYM (20 t ha-1), lime (250 kg ha-1) and NPK (20:30:10 kg ha-1) could be recommended for better plant establishment and higher yield in grain cowpea.