http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/623 2026-04-28T08:07:18Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/848 INFLUENCE OF PLANT DENSITY ON YIELD OF HYBRID MAIZE (Zea mays L.) UNDER SUPPLEMENTARY IRRIGATION Malaviarachchi, M.A.P.W.K; Karunarathne, K.M; Jayawardane, S.N Maize is an important cereal crop grown in Sri Lanka. Hybrid varieties are popular among farmers and the extent cultivated with hybrids has increased over the last few years. Department of Agriculture released the first local hybrid maize variety (Sampath) in 2004. Agronomic practices recommended for open pollinated varieties are not appropriate for highly input responsive hybrids. Therefore, a study was undertaken at Field Crops Research and Development Institute, Mahailluppallama for two consecutive seasons to determine a suitable plant density for hybrid maize. Four densities namely, 55555 (present recommendation), 74074, 88888 and 111111 plants/ha were tested with two varieties (Pacific 984 and Sampath) at 200kg ha-1 N, 100 kg ha-1 P2O5 and 50 kg ha-1 K2O. Grain yield increases observed in maha 2004/05 for 74074, 88888 and 111111 plants/ha were 88 kgha-1 (2%), 1114 kgha-1 (21%) and 1708 kgha-1 (30%) respectively and 247 kgha-1 (4%), 1434 kgha-1 (24%) and 1958 kgha-1 (33%) in yala 2005. Two varieties gave the same yields and variations in leaf area, plant height, ear length and 100 seed weight were found not significantly different. Seed number per ear was reduced by 10-16% at higher densities. Economic analysis revealed that profitability increased by Rs.7000.00- 11,000.00/ha both at 88888 and 111111 plants/ha densities. 2007-05-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/845 AN EVALUATION OF THE POTENTIALITY OF EXOGENOUS OSMOPROTECTANTS MITIGATING WATER STRESS ON CHICKPEA Bardhan, Kirti; Kumar, V; Dhimmar, S.K Chickpea is grown mainly as a non-irrigated post rainy season crop, therefore, to increase the economic competitiveness of chickpea, the management of drought is essential. A practice which can be used to enhance drought tolerance in plants is osmotic adjustment besides stomatal control. A field experiment was carried out at the College Farm of Navsari Agricultural University, Navsari during rabi 2003-04 to evaluate the potentiality of chemical(s) which could be used to ameliorate water stress and compensate yield reduction in chickpea under unirrigated condition. During investigation four chemicals viz., Glycine betaine (10 ppm 20 ppm), putrescine [16.11 ppm (10 µmol), 32.22 ppm (20 µmol)], PMA (10 and 20 ppm) and KNO3 (100 and 200 ppm) were evaluated along with water spray besides unirrigated and irrigated controls on two varieties of chickpea (GG-2 and Dahod Yellow). Aqueous solutions of chemicals were applied at 40 and 60 Days after sowing (DAS) on to the foliage. The results indicate that grain yield significantly declined due to water deficit. All foliar application of chemicals showed promising effect on crop health under unirrigated conditions. However, the significant effect was noticed with KNO3 (200 ppm). The plants following foliar application of KNO3 (200 ppm) attained significant increase in plant height, dry weight of plant, biomass, 100-seed weight and grain yield. For biomass it was found statistically equivalent to the irrigated control. Application of other chemicals was not as effective as KNO3 in alleviating stress. Glycine betaine showed significant improvement in dry weight and test weight yet it did not project potential yield of chickpea under unirrigated condition at Navsari. 0200-05-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/824 COMPARATIVE STUDIES ON IN-VITRO RESPONSE OF FRESH AND OLD CALLI OF RICE (Oryza sativa L.) Amarasinghe, A.A.Y; Yang, Y.S In-vitro responses of fresh and old calli of japonica variety, Taipei 309, and indica variety, Qiuguiai 11, were investigated with different culture procedures to develop an efficient protocol to improve the regeneration efficiency of long-term cultured calli of rice. Pre-culture media were used to restore the declined plant regeneration ability in long-term cultured calli. Both proliferation rates and regeneration efficiencies were compared between 2 varieties with fresh and old calli before and after using pre-culture media. It was clear that in-vitro culture responses were being declined after the second subculture of calli, indicating the loss of abilities to regenerate plants from long-term cultured calli in rice. An efficient protocol developed in this study with a pre-culture medium containing 10 mg/l BA,4 mg/l ABA, 1 mg/l NAA and 3% maltose showed 7-9 folds increase of in-vitro responses in longterm cultured old calli. This protocol not only restored the declined in-vitro ability, but also reduced the somaclonal variation, especially in indica variety, Qiuguiai 11. Furthermore, japonica variety, Taipei 309, performed well in the proliferation cultures before and after using pre-culture media, showing higher proliferation rates with both fresh and old calli, comparing with indica variety, Qiuguiai 11. Higher regeneration efficiencies with less number of albino plants were given by indica variety, Qiuguiai 11 throughout the study. This study clearly indicates that the invitro culture responses in rice depend mainly on the varieties of different subspecies, culture conditions and compositions, and the stages of the culture procedures. 2005-07-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/823 IMPACT OF WATER MANAGEMENT ON PRODUCTION OF RICE IN BALIPATNA COMMAND AREA OF ORISSA, INDIA Reddy, G.P In order to know the impact of improved water management practices a study was conducted at Balipatna block under canal irrigation command to know the economic feasibility of water management through field channels. Data from 30 farmers practicing irrigation through field channels and 30 farmers who are irrigating fields without field channels were collected with help of specially designed questionnaire. In order to know the impact of field channels, a multiple stepwise regression analysis with dummy variable to catch impact of field channels was done. The results indicated that irrigation through field channels had positive impact on the yield of kharif paddy. The variables like application of fertilizers, irrigation cost, seed and labour cost had significant positive impact on the paddy yields. The marginal productivity of inputs indicated fertilizers and seeds are not efficiently utilized compared other inputs. Hence, extension should be under taken to improve application of fertilizer in a more scientific way and encourage the use of yielding varieties to improve yields of paddy 2005-07-01T00:00:00Z