Browsing by Author "Presannakumari, K T"

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Analysis of bean characters in cocoa (Theobroma cacao L.) hybrids bred for bold beans
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2015) Rubeena, M; Presannakumari, K T
Evaluation of morpho-anatomical variation in Ocimum spp.
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1996) Lisymol J Vadukkoot; Presannakumari, K T
A comparative evaluation of the morphological and antomical features the protein pattern of the four different species of Ocimum viz., O. Tenuiflorum, O. Gratissimum, O. Basilicum and O. Canum was carried out in the Department of Plant Brreding and Genetics during 1994-95 to find out the evolutionary ralationships existing among the species and to prepare a key for their identification. Ample variability was observed among the four species of Ocimum for morphological and anatomical features as well as biochemical aspects. Based on these observations a key for identification of the species is proposed. From the morphological and anatomical observations made during the study it appears that O. Gratissimum and O. Tenuiflorum are phylogenetically related and so also O. Basilicum and O. Canum. The protein banding pattern of the four species further confirms this view. From the herbaceous nature, presence of pitted xylem vessel elements and vessels which are circular in Transverse Section it seems that O. Basilicum and O. Canum are more evolved than O. Tenuiflorum and O. Gratissimum.
Evaluation of reproductive biology and morpho-anatomical variations in Plumbago spp.
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2000) Subha, K; Presannakumari, K T
A comparative evaluation of the morphological and anatomical features as well as reproductive biology of the three species of Plumbago viz., P.rosea, P. zeylanica and P. capensis was carried out in the Department of Plant Breeding and Genetics during 1997-1999 with a view to find out the relationship existing among the species and to prepare a key for their identification. The different species of Plumbago varied with respect to nature of stem and leaves, colour of petiole, leaf attachment etc. Significant variations were also observed in the length of inflorescence, number of flowers per inflorescence time taken for completion of anthesis per inflorescence and size and colour of floral parts. Though there was uniformity in the fundamental structure of the stem, variations were observed in the outline of T.S., size of epidermal cells and arrangement of chlorenchyma. In the case of root, variability was observed in thickness of cortex, nature of stone cells, presence of starch grains etc. Study of reproductive biology revealed that anthesis occurred earlier in P. zeylanica compared to other two species. Further the period of anthesis also extended over a wide time range in P. zeylanica. Eventhough the pollengrains were tricolpate and spherical •in all the three species, differences existed with respect to colour, size and fertility of pollen grains. Coincidence of pollen dehiscence and stigma receptivity was found to lead good seed set in P. zeylanica. Apis spp. and wind were observed to be the main pollinating agents. Based on the different morphological, anatomical and reproductive characters a key for the identification of the different species were proposed. A distance matrix based on morphological anatomical and reproductive characters of three species revealed that P. rosea and P. zeylanica are more related than P. capensis.
Performance analysis of selected accessions of cocoa (Theobroma cacao L)
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2013) Asna, A C; Presannakumari, K T
The spreading cultivation of cocoa as an intercrop in states like Kerala, Tamil Nadu, Andhra Pradesh and Karnataka necessitated the development of high yielding hybrids with pest and disease resistance and adaptability to various agro climatic zones. The success of any hybridization programme particularly in perennials depends on the proper selection of parental lines having genetic divergence. The present study entitled “Performance analysis of selected accessions of cocoa (Theobroma cacao L.)” was taken up in this background at COH, Vellanikkara during 2011-13 to evaluate and characterize the selected cocoa accessions and to assess the genetic divergence among them. Fifty accessions of cocoa comprising of both exotic and indigenous ones which are in the full bearing stage and maintained at Cocoa Research Centre, Vellanikkara formed the material for the study. These accessions were subjected to morphological and biochemical evaluation. The morphological evaluation based on 13 qualitative and 25 quantitative characters was done using the descriptor developed by Bekele and Butler (2000). Fat and total polyphenol contents were estimated following standard procedures for biochemical characterization. The clustering of the accessions based on these characters was done by unweighted pair group method (Sneath & Sokal, 1973) and the genetic divergence was estimated by D2 statistics developed by Mahalonobis (1936). Wide variability was observed among the accessions for all the qualitative traits except colour of staminodes and hardiness of husk. Variations expressed by the accessions in terms of both floral and pod quantitative traits were also high. Among the exotic accessions, COCA 3370-3 was having the highest pod weight, pod length, pod breadth, ridge thickness and furrow thickness. However, its wet bean weight accounted only for 14.79 percent of the pod weight. Among the indigenous types, Konni local 2 was the best performer for these traits. The characters of economic interest viz., pod weight, number of beans/pod, dry weight of peeled bean, percentage of flat beans/pod and pod index ranged from 318.67g to 1268.33g, 22.93 to 49.27, 0.58g to 1.72g, 0.00 to 12.60 percent and 12 to 49 respectively among the exotic accessions. The corresponding traits in the case of indigenous accessions ranged from 416.67g to 719.33g, 31.60 to 46.27, 0.93g to 1.52g, 0.75 to 7.86 percent and 17 to 34 respectively. Among the accessions evaluated R (10) (MEX) was found to be a desirable one with low pod index value (12) and flat bean content/pod (0.81%) coupled with high number of beans/pod (49.20) and dry weight of peeled bean (1.68g). This is followed by EET 400 having a pod index of 15. The exotic accessions Criollo, KER 9 and CLM 90 failed to satisfy the international standard for dry weight of peeled bean viz., 0.8g or more. The fat content ranged from 40 percent to 60 percent and total polyphenol content from 2.25 percent to 9.09 percent. The cluster analysis based on qualitative and quantitative characters resulted in nine and seven clusters respectively for exotic accessions and five and three clusters respectively for indigenous ones. The accessions belonging to same qualitative cluster were found to fall in different quantitative clusters indicating that even though they are similar at qualitative level they are different at quantitative level. With respect to biochemical characters majority of accessions were remaining as independent units even at one percent similarity level and hence could not be clustered. Among the exotic types, the maximum genetic divergence was observed among the accessions falling in quantitative cluster I and V as indicated by the highest inter cluster distance (33763.40). In the case of indigenous ones maximum divergence was found among the accessions falling in cluster I and II (148447.4). Mealy bug and tea mosquito bug were the major pests and black pod was the major disease affecting the pods resulting in yield loss. Besides, rodents like rats and squirrels also caused damage to the pods. Among the accessions evaluated, COCA 3370-3 having high husk thickness was found to be tolerant to the major pests and diseases affecting the pods and can serve as donor parent in resistance breeding programme. A statistical key was developed using key qualitative and quantitative characters which can serve as a preliminary tool for predicting the performance of the accessions.
Reproductive biology and enzyme studies in ocimum
(Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 1997) Fancy Parameswaran; Presannakumari, K T
The present study on "Reproductive biology and enzyme studies in Ocimum spp." was undertaken at the Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara during the period 1994-1996 with a view to make a comparative evaluation of the reproductive biology and phosphorylase enzyme activity of different species of Ocimum. The four species of Ocimum viz. O. tenuiflorum, o. gratissimum, o. canum and o. basilicum collected and maintained in the Department were used for the study. The different species of Ocimum varied significantly in the time taken for inflorescence development, completion of anthesis in an inflorescence, number of flowers per inflorescence and distance between verticils. Species level variations were also observed in seed moisture content, seed density, l000-seed weight and seed dormancy period. Flowers of the four selected species were identical in basic structure although there existed variation in size, colour, hairyness and shape of floral parts. Anthesis occurred earlier in o. canum than the other three species. Pollen grains of Ocimum were hexacolpate and reticulate. However, species level difference existed in the size, shape and fertility of pollen grains. No self incompatibility mechanism existed in the four species studied. The floral morphology and protandrous nature makes the species adapted to cross pollination. Insects and ants are the main agents of pollination. Comparison of Sanctum and Basilicum groups revealed that Sanctum group which includes o. tenuiflorum and O. gratissimum required longer time for inflorescence development than Basilicum group which includes o. canum and O. basilicum. Verticils were closer in the inflorescence of Sanctum group than Basilicum group. Sanctum group produced less conspicous flowers with sessile bracts and yellow pollen grains. In this group anther dehiscence occurred in bud stage. Basilicum group produced conspicous flowers with pedicellate bracts and white pollen grains. Anther dehiscence was after flower opening in this group. Dormancy break was sudden in Sanctum group and gradual in Basilicum group. Moisture content of Ocimum seeds was positively related to phosphorylase enzyme activity. Phenol content was negatively related to both moisture content and phosphorylase enzyme activity of the seeds.