http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/642 Wed, 08 Apr 2026 02:19:30 GMT 2026-04-08T02:19:30Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/864 GENETIC ENHANCEMENT OF SUGARCANE (Saccharum sp. hybrids) FOR RESISTANCE TO RED ROT DISEASE AND ECONOMIC TRAITS Babu, C; Koodalingam, K; Natarajan, U.S; Shanthi, R.M; Govindaraj, P The present experiment was conducted at Sugarcane Breeding Institute (ICAR), Coimbatore to generate diverse genetic stocks for resistance to red rot disease caused by Colletotrichum falcatum Went. and other important economic traits. This study was carried out with progenies obtained from 39 crosses involving 45 parental clones of interspecific and intervarietal origin. The interspecific origin involves diverse forms of Saccharum officinarum and S. spontaneum that are hitherto unutilized in the breeding programme. The progenies were evaluated for resistance to red rot disease and economic traits such as cane yield and quality. Out of 39 crosses investigated for race specific resistance as a qualitative trait, 18 crosses showed a simple Mendelian segregation of monogenic nature. Parent progeny regression analysis suggested that about 50% of the variation in the population could be attributed to additive genetic variance (horizontal resistance). Two crosses involving susceptible parents viz., 971235 (S) x Co 1148 (S) and Co 88028 (S) x Co 775 (S) contributed 28-30% resistant progenies. These transgressive segregants are likely to be stable in their resistance due to additive genetic action and could be used as donor parents in red rot resistance breeding programmes for imparting race non-specific resistance. The present investigation has also identified some specific cross combinations for yield, quality in addition to red rot resistance for further exploitation in breeding programme. Tue, 01 Sep 2009 00:00:00 GMT http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/864 2009-09-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/861 EFFECT OF PARTICLE SIZE OF GLIRICIDIA LEAVES AND SOIL TEXTURE ON N MINERALIZATION Walpola, B. C; Arunakumara, K. K. I. U Decline in soil productivity and environmental quality in the tropics have led to a search for new methods to sustain crop production via more efficient nutrient cycling. In tropical agricultural systems with limited access to fertilizers, plant residues are often used to meet the nutrient requirements of most of the crops. In this regard, leguminous residues are an important source of N used in low input agricultural systems. The present laboratory investigation was conducted to elucidate the effect of the particle size of Gliricidia leaves (S1 ≤ 0.5 mm, S2 = 4 mm) and texture of soil (T1 = sandy clay loam, T2 = loamy sand) on N mineralization. Results revealed that the pattern and the amount of NH4 + -N released from two soil types were significantly (P ≤ 0.05) different. The highest amount of NH4 + -N (82 mg/kg soil) was released at 21st day of incubation from sandy clay loam soil treated with the particle size of 4 mm. However, in the case of NO3 - -N, loamy sand soil showed higher cumulative NO3 - -N content than that of in sandy clay loam soil. The highest amount of NO3 - - N (68 mg/kg soil) was released at 21st day of incubation from loamy sand soil treated with the particle size of ≤ 0.5 mm. Results could be concluded that nitrogen mineralization of Gliricidia leaves were affected by the texture of the soil as well as the particle size of the Gliricidia leaves. The present findings therefore stress the importance of standardizing residue particle size as it determines the rate of N mineralization in a given soil. Tue, 01 Sep 2009 00:00:00 GMT http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/861 2009-09-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/859 OCCUPATIONAL STRESS AMONG FARMING PEOPLE Ramesh, A.S; Madhavi, C During the last 25 years, agricultural sector has gone through lot of changes and it also found to be one of the potential areas for stress. Greater use of automation technology, more use of organic production, decrease price for agricultural products and new complicated legislations have made the life of farmers more stressful one. In this study an attempt is made to find out the potential factors which cause stress and made the life of farming community more miserable. Results have clearly indicated that the occupation farming leads to stress due to financial, weather, work overload, social interaction and farm hassles. It is inferred that all the selected dimensions are producing either high or medium level of stress to farming people. It is also found that stress due to financial factors is found to be slightly higher than other stresses. Tue, 01 Sep 2009 00:00:00 GMT http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/859 2009-09-01T00:00:00Z http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/858 SYMBIOTIC DIVERSITY AMONG ACID-TOLERANT BRADYRHIZOBIAL ISOLATES WITH COWPEA Appunu, C; Reddy, L. M. L; Reddy, C. V. C. M; Sen, D; Dhar, B A total of eight acid tolerant strains of bradyrhizobia isolates from indigenous cowpea plants grown in acid soil in Varanasi, Uttar Pradesh, India, were examined for their ability to survive in soil and yeast extract mannitol broth at low pH levels. All these isolates survived in acidic (pH 3.5-6.5) conditions. Survival capacity of rhizobia was higher in soil than in nutrient medium at low pH 3.5-6.5 levels. Symbiotic effectiveness of these strains under polyhouse conditions in sterilized soil of pH 4.5 recorded the highest and lowest symbiotic characters for dry matter production and nitrogen improvement per plant in CR09 and CR20 inoculated plants, respectively. All the examined isolates showed variability in their symbiotic performances. The strain found to be more tolerant to stress were more effective N2 fixers in symbiosis with cowpea cv. Paiyur1 under acid-soil conditions. Symbiotic variation among different strains showed that there is potential to improve strain performance under stress conditions. Tue, 01 Sep 2009 00:00:00 GMT http://repo.lib.sab.ac.lk:8080/xmlui/handle/123456789/858 2009-09-01T00:00:00Z