1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Integrated weed management in blackgram [Vigna mungo (L.) Hepper] with pre-mix herbicides.(Department of Agronomy, College of Agriculture, Vellayani, 2025-05-05) Ameena, MAn investigation entitled ‘Integrated weed management in blackgram [Vigna mungo (L.) Hepper] with pre-mix herbicides’ was conducted at College of Agriculture, Vellayani during 2022-2024. The major objective was to formulate an integrated weed management strategy using pre-mix herbicides for black gram intercropped in coconut garden. The field experiment was conducted at the Instructional Farm, Vellayani during the summer season from February to April 2024 in a coconut garden with palms above 40 years of age. The experiment was laid out in randomized block design with nine treatments replicated thrice. The weed management practices tested were: T1- pre emergence (PE) pendimethalin + imazethapyr (premix 1) 800 g ha-1; T2 - T1 followed by (fb) hand weeding (HW) at 30 days after sowing (DAS); T3- post emergence (PoE) propaquizafop + imazethapyr (premix 2) 125 g ha-1; T4- T3 fb HW at 40 DAS; T5- PE pendimethalin 1kg ha-1 fb HW at 30 DAS; T6- PE pendimethalin 1kg ha-1fb PoE imazethapyr 50g ha-1; T7- PE pendimethalin 1kg ha-1 fb PoE propaquizafop 100g ha- 1; T8- HW at 15 and 30 DAS; T9- weedy check. The blackgram variety DBGV-5 treated with Bradyrhizobium inoculant BMBS 47 was dibbled in the interspaces of coconut and managed as per the KAU Package of Practices. Pre emergence herbicide was applied on the next day of sowing and post emergence applied at 15 DAS. Symptoms of phytotoxicity were observed in crop as mild stunting in plots sprayed with premix combination, pendimethalin + imazethapyr which persisted upto 10 days after herbicide application. The results of the study revealed that weed management practices had no significant influence on the growth attributes of blackgram. However, the yield and yield attributes were significantly influenced by the weed management practices. Higher pods per plant was recorded in T4 (36.00) and was comparable with T7 (35.83) while weedy check recorded the lowest number of pods (14.24). Hundred seed weight was recorded higher in T2 (5.33 g) and was on par with T4 (5.17 g) and T1 (5.13 g). The highest seed yield per plant was recorded in T4 (9.60 g) followed by T7 (9.23g), T6 (8.3g) and T5 (8.23g). Post emergence application of premix 2 fb HW at 40 DAS resulted in higher seed yield per ha (1793 kg) and was comparable with T7 (1731 kg). Higher haulm yield per ha was recorded in T5 (3658 kg) and was comparable with T4 (3616 kg), T6 (3581 kg) and T7 (3485 kg). The study observed that absence of weeding led to the highest yield reduction in blackgram, with a weed index of 54.44 per cent while yield reduction was lower in T4 (2.45%) and on par with T7 (5.35%). The predominant weed flora in the experimental field was grasses. However, more diversity was observed in the flora of broad leaf weeds. Pre emergence application of premix 1 fb HW at 30 DAS resulted in significantly lower weed density and weed dry weight and higher weed control efficiency at all stages of observation and was comparable with T7, T4 and T6. At 30 and 45 DAS, T1, T2, T5, T6 and T7 resulted in lower relative biomass of grasses that was comparable with T4 and the highest relative biomass of grasses was recorded in weedy check (85.92 %). Treatments involving both pre- and post-emergence herbicide applications (T7 and T6) resulted in higher dehydrogenase enzyme activity at 30 DAS, while their combination with hand weeding (T4, T5) showed increased activity at 45 DAS. Weed management practices significantly influenced nutrient uptake, with T7 and T1 exhibiting higher N, P and K uptake. The integration of premix herbicides with hand weeding and use of pre and post-emergence herbicides, significantly reduced N, P, and K removal by weeds throughout the growth period. The BC ratio varied significantly among the weed management practices with the highest in T4 (1.95), followed by T7 (1.94), with the lowest ratios in hand weeding twice (1.05) and weedy check (0.82). Weed management practices significantly influenced the population of Bradyrhizobium, fungi and actinomycetes in rhizospheric soil at 30 DAS with T2 showing higher count and on par with T1. However, no significant differences were noted in the population of phosphorus solubilising bacteria across all time points. The in vitro sensitivity test of Bradyrhizobium to premix 1 and 2 at concentrations of 800 to 2000 ppm and 175 to 325 ppm respectively showed positive growth with no inhibition zones around the sterile disc containing herbicide mixture placed on a lawn of Bradyrhizobium in the medium. The study identified application of propaquizafop + imazethapyr 125 g ha-1 at 15 DAS fb HW at 40 DAS; and application of pendimethalin 1kg ha-1 on the next day of sowing fb propaquizafop 100g ha-1 at 15 DAS as the most effective weed management strategies in terms of yield, weed control efficiency and gross return in blackgram. Considering economics, application of propaquizafop + imazethapyr at 15 DAS fb HW at 40 DAS could be adjudged as the most effective integrated weed management strategy for achieving higher seed yield in blackgram intercropped in coconut garden.Item Productivity enhancement of blackgram (Vigna mungo (L.) Hepper) intercropped in coconut gardens(Department of Agronomy, College of Agriculture,Vellayani, 2021) Pooja, A P; Ameena, MThe research work entitled ‘Productivity enhancement of blackgram (Vigna mungo (L.) Hepper) intercropped in coconut gardens’ was undertaken at College of Agriculture, Vellayani during 2018-2021. The study aimed to identify shade tolerant blackgram varieties suitable for coconut gardens, to study the effect of foliar nutrition and plant growth regulators on growth and yield of the shade tolerant blackgram varieties intercropped in coconut garden and to work out the economics of cultivation. The investigation was carried out as two experiments: (i) screening of blackgram varieties for shade tolerance, and (ii) performance evaluation of shade tolerant varieties under foliar application of nutrients and growth regulators in rainfed coconut garden. The first experiment was conducted during Rabi 2019-20 in coconut garden having a light intensity equivalent to 50 per cent of that under open condition (56.25 klux), planted at a spacing of 7.6 m x 7.6 m. Seeds of 12 promising blackgram varieties collected from different research stations of south India (Sumanjana, DU 1, DBGV 5, VBN 5, VBN 6, VBN 8, Rashmi, CO 6, TAU 1, TAU 2, Blackgold and AKU 15) and three cultures (Culture 4.5.8, Culture 4.5.18 and Culture 4.6.1), were raised in micro plots laid out in randomized block design with three replications. The crop was raised as per KAU package of practices. The results of the study revealed significant variation in growth characters among the varieties screened for shade tolerance under partial shade in coconut garden. Plants of DBGV 5 were significantly taller (96.89 cm) with higher initial number of leaves at all the stages and was on par with Sumanjana and CO 6. Higher leaf area index (LAI) and leaf area duration were recorded in CO 6 (5.77, 65.66 days) and DBGV 5 (5.36, 58.40 days) followed by Sumanjana. Early flowering was observed in Sumanjana (34.33 days) and DBGV 5 (36.33 days). The variety DBGV 5 had the highest photosynthetic rate and resulted in significantly more pods per plant (23.67) which was on par with CO 6, VBN 5, VBN 6, Sumanjana and Rashmi. DBGV 5 produced the highest seed yield per plant (5.44 g) followed by VBN 5 and Sumanjana. Haulm yield per plant was higher for DBGV 5 (19 g) and was on par with VBN 5, Sumanjana and CO 6. The variety DBGV 5 produced the highest seed yield (1183 kg ha-1 ) followed by VBN 5, Sumanjana and CO 6. A higher harvest index of 0.24 was recorded by Sumanjana which was on par with DBGV 5 and VBN 6. Among the varieties screened, five varieties which performed better in terms of yield per unit area under the partial shade in coconut garden viz., DBGV 5, VBN 5, Sumanjana, CO 6 and VBN 6 were selected for experiment II undertaken in summer 2020 followed by the confirmatory trial during Rabi 2020 -21. The experiment was laid out in split plot design with five varieties (v1 - Sumanjana, v2 - DBGV 5,v3 - VBN 5,v4 - VBN 6,v5 - CO 6) as main plot treatments and six foliar sprays of nutrients and plant growth regulators as subplot treatments (f1: 19:19:19 (1%) at 45 and 60 DAS, f2: SOP (0.5%) at 45 and 60 DAS, f3: NAA 40 mg L-1 and salicylic acid 100 mg L-1 at pre-flowering (30-45 DAS) and 15 days later, f4: f3 + f1, f5: f3 + f2 and f6: Control - KAU POP). Among the varieties, Sumanjana (v1) grew taller during both the seasons and was comparable with CO 6 and DBGV 5 at harvest. Sumanjana produced higher number of branches with more number of leaves during both the seasons. At flowering, higher LAI, number and dry weight of nodules per plant were realized by Sumanjana and was on par with CO 6 (v5) in summer and DBGV 5 (v2) in Rabi. Sumanjana exhibited the highest crop growth rate (CGR) and relative growth rate (RGR) during both the seasons at 45-60 DAS. However, DBGV 5 recorded the highest net assimilation rate (NAR) between 30-45 DAS and 45-60 DAS during both the seasons. The highest chlorophyll content was recorded by DBGV 5 (1.96 mg g-1 fresh tissue) during summer and by Sumanjana (2.36 mg g-1 fresh tissue) during Rabi. The highest stomatal conductance (30.22 m moles m-2 s -1 and 28.34 m moles m-2 s -1 ) and lower stomatal index (15.16% and 13.34%) were recorded in Sumanjana during both the seasons. The variety Sumanjana flowered earlier compared to other varieties during both the seasons and produced the highest number of pods per plant (27.30 and 26.54). Hundred seed weight was significantly higher for DBGV 5 (5.01 g and 4.92 g) and remained at par with Sumanjana (4.99 g and 4.88 g) during both the seasons. Seed yield, haulm yield and total dry matter production (TDMP) were higher for Sumanjana and comparable with DBGV 5 during both the seasons. Sumanjana recorded higher NPK uptake during both the seasons followed by DBGV 5. The subplot factor foliar spray had significant effect on growth, physiological and yield attributes of blackgram varieties. Foliar spray of 19:19:19 (1%) at 45 and 60 DAS + foliar spray of NAA 40 mg L-1 and SA 100 mg L-1 at pre-flowering and 15 days later (f4) resulted in significantly taller plants, more number of branches and leaves. The highest CGR, RGR (at 45-60 DAS), LAI, number and dry weight of nodules per plant at flowering were recorded in f4 during both the seasons. During summer, f3, f4 and f5 recorded higher NAR between 45-60 DAS. Higher chlorophyll content and stomatal conductance were recorded by f4 during both the seasons. Plants supplied with f3 attained 50 per cent flowering earlier and was on par with f5 during both the seasons. Highest number of pods per plant, 100 seed weight, seed yield, haulm yield and TDMP were recorded by f4 during both seasons. The grain protein content was improved by f4 and was on par with f3, f1 and f5. The NPK uptake was higher in f4 and was on par with f3 and f5 during summer. Significantly higher organic carbon, available N and P was recorded in f4. Among the treatment combinations, Sumanjana (v1) with f4 produced taller plants at two months after sowing (MAS), higher number of branches and leaves per plant during summer and Rabi. Leaf area index, number of nodules and dry weight of nodules at flowering were higher for v1f4 followed by v2f4. Sumanjana in combination with f4 measured significantly higher CGR and RGR (at active growth stages), highest chlorophyll content, stomatal conductance and lower stomatal index during both the seasons. The variety Sumanjana with f4 produced superior number of pods per plant (30.24 and 29.40) and hundred seed weight during summer and Rabi. A higher seed yield was realized in v1f4 (1750 kg ha-1 ) which was on par with v2f4 (1713 kg ha-1 ) during summer. Seed yield was the highest (1700 kg ha-1 ) in v1f4 during Rabi. Haulm yield and TDMP recorded were higher for v1f4 and was on par with v2f4 during both the seasons. The available N status in soil was higher during both the seasons in v1f4 with the highest NPK uptake during Rabi. Sumanjana and DBGV 5 with f4 realized higher mean net income (₹ 70411 ha-1 and ₹ 61256 ha-1 ) and mean B: C ratio (2.04 and 1.95). The present study identified DBGV 5 and Sumanjana as shade tolerant blackgram varieties with superior growth and yield attributes under partial shade and could be recommended for intercropping in coconut garden. Further, the yield of the shade tolerant varieties could be enhanced by recommended dose of nutrients as per KAU package supplemented with foliar spray of 19:19:19 (1%) at 45 and 60 DAS + foliar spray of NAA 40 mg L-1 and SA 100 mg L-1 at preflowering (35 DAS) and 15 days later. Sumanjana and DBGV 5 raised under partial shade in coconut garden with recommended dose of nutrients supplemented with the above said foliar spray realized higher mean net income and mean B: C ratio.Item Mutagenicity of gamma rays and EMS on winged bean (Psophocarpus tetragonolobus (L.)(Department of Plant Breeding and Genetics, College of Agriculture, Vellayani, 1995) Deepa, T O; Radha Devi, D SItem Potential for drought tolerance in blackgram (Vigna Mungo L. Hepper)(Department of Plant Breeding, College of Agriculture, Vellayani, 1989) Sudha Rani, S; Ramachandran Nair, NAn investigation was carried out in the Department of Plant Breeding, College of Agriculture, Vellayani to evaluate the drought tolerance potential of twenty genotypes of blackgram under moisture stress situation. The variability present in the population was studied and a selection index was worked out to identify desirable genotypes from undesirable ones. The varieties were evaluated for yield, yield components and other drought tolerant parameters in a field trial in Randomised Block Design with three replications. The varieties tested showed significant difference for most of the drought tolerant parameters. Genotypic coefficient of variation was maximum for free proline content of leaves and minimum for days to first flowering. Days to maturity, grain-filling period and hundred seed weight exhibited high heritability indicating lesser environmental influence on these characters. Moderate to high heritability and appreciable genetic advance was recorded by leaf area, root/shoot ratio and free proline content of leaves. The correlation study has revealed that leaf area, free proline content of leaves, root spread, number of pods per plant, number of grains per pod, hundred seed weight and grain size showed positive correlation with grain yield. Days to first flowering, days to maturity and grain-filling period were found to be negatively correlated with grain yield. A selection index based on yield, yield components and drought tolerant parameters like leaf area, grain- filling period, root/shoot ratio and free proline content of leaves was found to be relatively more efficient than direct selection for yield. Based on index values, five genotypes were found to be drought tolerant. It can be concluded from the present study that an ideal plant type in blackgram for drought prone area should have early maturity, moderate leaf area, fewer number of stomata, short to medium grain-filling period, high root length and spread and moderate number of pods having maximum grain number and size.