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Item Hybrid inviability and weakness in certain indica rice crosses(Kerala Agricultural University, 1980) Kumaran, K; Madhava Menon, P; Rathinam, AThe existence of a partial reproductive isolation in the form of hybrid inviability and weakness supplemented by hybrid sterility was evident in four crosses of PTB 7 with PTB 10 and CO 29. F: plants were inviable or weak and were characterised by stunted growth, less tillering, late flowering and high spikelet sterility. Selfed progenies of weak Fj plants showed segregation for weak and inviable and normal plants in definite ratios. However, hybrids between PTB 10 and CO 29 were normal. The lethality and weakness of plants in fl and later generations were found to be determined by the action of a pair of complementary dominant lethal genes, one of which was present in PTB 7 and the other present commonly in both PTB 10 and CO 29.Item Correlation between seed and seedling characters in jack (Artocarpus Heterophyllus L.)(Kerala Agricultural University, 1980) Nazeem, P A; Gopikumar, K; Kumaran, KItem Effect of methods of fermentation on temperature, acidity and quality of cocoa (Theobroma cacao L.) beans(Kerala Agricultural University, 1981) Adomako, D; Vikraman Nair, R; Kumaran, KThe trend of variation in temperature, and pH of cocoa beans in heap and tray methods of fermentation was studied at the Cocoa Research Institute of Ghana. Heaps of sizes having 50 kg, 150kg, and 450 kg and the standard tray method of fermentation were tested and the grades of dried beans obtained from the different methods were compared. In the heaps, a higher peak temperature was reached as compared to the trays. The beans in the heaps followed regular fluctuations in temperature during fermentation while the temperature fluctuations were low in the trays. The final pH values of pulp and beans were not much affected by the method of fermentation and heap size However, the decrease in pH of cotyledons was slower in the largest heap The fermentation methods and heap sizes did not markedly affect the grade of the dried beans.Item Curing bud wood and method of budding on 'bud take' in cocoa var. forastero (Theobroma cacao L.)(Kerala Agricultural University, 1982) Kumaran, K; Sivaraman Nair, P CItem Evaluation of jack fruit (type 'varikka') for pectin(Kerala Agricultural University, 1982) Vilasachandran, T; Kumaran, K; Gopikumar, KItem Vegetative propagation in jack (Artocarpus Heterophyllus Lam)(Kerala Agricultural University, 1984) Nazeem, P A; Gopikumar, K; Kumaran, KStudies were conducted on vegetative propagation of jack. Grafting, budding and layering were tried. Approach grafting was found successful. All other methods of grafting, budding and layering on bearing tree gave negative results. Layering on one year old seedlings gave very good results. Best results were obtained with ring layering done within 10 cm from bottom of the plant with coconut pith as the media. Since juvenile factor is supposed to play an important role in rooting, it may be possible to propagate jack vegetatively by inducing new shoots near the collar region of the selected mother plants and then undertaking layering on these new shoots.Item Morphology of the inflorescence and fruit in jack (Artocarpus Heterophyllus Lam.)(Kerala Agricultural University, 1995) Tessy Joseph; Kumaran, KThe iiiflorescence in jack is a catkin. The individual flowers are radially arranged on a lleshy peduncle. The perianth tubes of male flowers are free from each other, while those of female (lowers are fused in the middle region. Androecium consisted of a single stamen with a hasifixed four celled anther. Gynoecium consisted of a white waxy clavate stigma, a slender style and a unicelled ovary with a solitary ovule inside, attached by marginal placentation. The female catkin after pollination developed into a large composite fruit (sorosis) which is a 'false fruit', with the persistent perianth forming the hulk of the f r u i t . The 'tnie fruit' resembled an achene. Except for the texture of the flakes after ripening, the two types studied had the same morphological features; the 'koo/.ha' with soft mushy Hakes an 'varikka' with crisp hard flames.Item Fruit set, fruit development and eruit drop in hard and soft flaked types of jack (Artocarpus heterophyllus Lam.)(Kerala Agricultural University, 1996) Tessy Joseph; Kumaran, KStudies on fruit set, fruit drop and fruit development in ' Varikka' and ' Koozha' types of jack (Artocarpus heteropkylhis Lam.) have indicated that the fruit set under natural condition was 83.335?,. The post-set drop ranged from 3040% in the two types studied. The peak period of drop was observed between the 60th and 80th day after emergence of the catkin. The time required for full development of fruit ranged from 100 to 138 days. Growth of fruit showed a sigmoid pattern, the rate being rapid up to the first 80 days and thereafter declined gradually The two types 'Varikka' and 'Koozha' did not vary significantly in any of the above characters.Item Flowering, floral biology and pollination in hard and soft flaked types of jack (Artocarpus heterophyllus Lam.)(Kerala Agricultural University, 1996) Tessy Joseph; Kumaran, KInvestigations'on the floral characters of "Varikka' and "Koozha' types of jack (Artocarpus heterophyllus Lam.) were conducted at the Agricultural Research Station, Mannuthy, Trichur on 14 mature trees. There was no significant difference between 'Varikka' and 'Koozha' types in respect of any of the characters studied. The pattern of male and female catkin production was found to differ in jack, the former occurred from October to February while the later was confined to only three months starting from late November to February. In a male catkin, anthesis started by 6 a.m. and continued up to 6 p.m. in a day. This pattern continued for 5 to 7 days in a catkin. Anther dehiscence occurred between 6 p.m. and 7 p.m. on the day of its emergence. The sequence of emergence of stigma on the female catkin was highly erratic and continued for 3 to 4 weeks. Complete fading away of the stigma occurred in 21 to 35 days after anthesis started. The chief agent of pollination was found to be wind although certain amount of insect pollination cannot be ruled out.Item Influence of weather on the yield of pepper cv. panniyur 1 (Piper nicrum L.)(Kerala Agricultural University, 1999) Pradeepkumar, T; Kumaran, K; Aipe, K C; Manomohandas, T PInfluence of weather on the yield of black pepper variety Panniyur 1 was studied by resorting correlation and regression analysis. Among the different weather variables, mean maximum temperature in March first fortnight and June second fortnight, total sunshine hours received during February first fortnight, March first fortnight and April second fortnight, total rainfall during March second fortnight and September second fortnight- mean maximum relative humidity during March first fortnight and mean minimum relative humidity during March second fortnight and July first fortnight were found to be significantly correlated with the pepper yield of succeeding year. By combining three weather variables viz., mean maximum temperature during March first fortnight, mean maximum temperature during June second fortnight and mean minimum relative humidity during July first fortnight, a regression equation was derived with an R2 can be used in predicting the pepper yield at the end of July first fortnight.