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ThesisItem Open Access Flower bud differentiation in clove, Eugenia caryophyllus (Sprengel) Bullock & Harrison(Faculty of Agriculture, Department of Horticulture, College of Agriculture, Vellayani, Trivandrum, 1989) Pauline Lina, Edwin; KAU; Vasanthakumar, KInvestigations on flower bud differentiation in clove were carried out at College of Agriculture, Vellayani from August, 1936 to December, 1987. Bearing clove trees (seven years old) at the Instructional Farm attached to the college were utilized for the study. The plant specimens were stored in FAA (Formalin-acetoalcohol) and then dehydrated through tertiary butyl alcohol - iso propyl alcohol series. The specimens were Infiltrated and embedded In paraffin wax (m.p. 58-60'C) and sectioned In a rotary microtone. The sections were then de-waxed, stained and examined for the anatomical features and photoalerogra- phed. The weather parameters and the nutritional factors recorded daring the period of study and those during sixteen fortnights prior to differentiation, were correlated with the data on flower bud differentiation. Significant positive correlation was obtained between the maximum temperature during the sixth to tenth fortnights before differentiation and the percentage of flower buds differentiated. Sunshine hours during ninth to twelfth fort night prior to differentiation showed a positive correlation with the percentage of flower bud differentiation.ThesisItem Open Access Cytogenetic studies on intervarietal hybrids of sesamum (Sesamum indicum L.)(Department of Agricultural Botany, College of Agriculture Vellayani, Trivandrum., 1984) Chandramony, D; KAU; Krishnan Nair, NThesisItem Open Access Estimation of induced variability in chillies(Department of agricultural botany , College of agriculture Vellayani, Trivandrum., 1985) Lekha Rani, C; KAU; Krishnan Nair, NThe mutagenic effect of Co-gamma rays and Ethylmethane sulphonate on three different chilli varieties have bean studied in detail in generation U3 ing two moderate doses of gamma rays <20 and 30 kR) and two concentrations of ISMS (0.5 and 1*0 par cent)* The presence and extent of chimeras and their relation to induced variability was assessed by raising branch-wise progenies in ^ generation* The experiment was conducted during 1982-84 at the Department of Agricultural Botany# College of Agriculture, Vellayani* The generation was laid out in RBD and in splitplot design with proper randomisation and replications* The crop wa3 raised and maintained following the Package of Practices recommended. The polygenic traits analysed in a, generalisen include plant height, number of branches per plant, fruit yield per plant and length and weight of fruits. The data collected were statistically analysed for proper interpretation of tho results obtained. It has been observed in almost all the polygenic traits that the extent of variability created vary depending on the genotypes, mutagen and their dosos and character under observation. The mean values wer« found to shift both in negative and positive directions to control values• significant shift in mean values depending on the type of branch category clearly demonstrates that there exists the mechanism of diplontlc selection in this particular crop variety# when exposed to mutagens. But the extent of selection varies depending on the mutagen and their doses and the genotypes concerned. a significant negative shift in mean Value was noted only in the case of fruit weight under both the concentrations of EM3 and 20 kR gamma rays whereas a positive or negative insignificant shift was noted in all other characters under both the mutagens, when under EM3 and in gansna rays showed a negative shift* positive shift in mean value wes noted in majority of the cases for number of branches per plant. Fruit length and weight and number of seeds per fruit showed a negative shift in majority of the cases analysed# but fruit number and yield per plant showed a reverse trend. The shift in mean value under the different branch categories varied depending on the varieties# mutagens and their doses and also the character under study. The phenotypes were found toAdistributedboth in negative and positive directions to control group in all the characters analysed. The frequency distribution whether negative or positive varied depending on the mutagen and their doses# the genotypes and character under study. In majority of tha cases the maximum frequencies of positive variants under both the concentrations of EMS and under 0.5 per cent for negative variants were found to be in the early formad branches when it was in the later ones is tha case of negative variants under 1.0 per cent EMS. in the case of gamma rays this general trend was not observed* The data analysed clearly demonstrate the existence of diplontic selection and promises wide scope for positive selection response either in negative or positive directions.ThesisItem Open Access Standardisation of in Vitro Propagation Technique In Gymnema Sylvestre R. Br.(Department of Plantation Crops and Spices, College of Horticulture,Vellanikkara, 1993) Anu, K I; KAU; Nazeem, P AA study was taken up in the Department of plantation Crops and Spices, College of Horticulture, Vellanikkara, During 1991-93, to standardize the in vitro technique for multiplying Gymnema sylvestre R. Br. Which is locally known as ‘Gurmar’. This being the first attempt of micropropagation in this crop , the methodology was to be standardized, from the initial stage itself . Nodal segments, leaf segments as well as stem segments collected from mature vines maintained in the college of horticulture were used as explants in the present study. Different routes like enhance release of axillary buds, organogenesis and embryogenesis were attempted for the plant. The main limitation in establishing in vitro cultures of Gymnema sylvestre was identified to be microbial interference, which was mainly due to the fungus collectotrichum sp. Great seasonal variation was observed for the fungal interference and the period from January to April was identified as the best season for establishing the cultures of Gymnema sylvestre was identified to be microbial interference, which was mainely due to the fungus Collectotrichum sp. Great seasonal variation was observed for the fungal interference and the period from January to April was identified as the best season for establishing the cultures of Gymnema sylvestre. Mercuric chloride at 0.1 per cent level was identified as the best surface sterilant , with the survival rate being 82 to 94 percent according to the explant material used. Basal medium MS supported the cultures of leaf segments while the inorganic salts were to be reduced to half level for supporting the cultures of stem segments. Out of the various growth regulator combinations tried for bud break and healthy shoot elongation in Gymnema, kinetin and IAA could support bud break and healthy shoot production . Coconut water and adenine sulphate when supplemented in the medium favoured healthy shoot induction . Survival rate of newly formed shoots were very poor due to leaf abscission. Higher levels of MgSo4 in the medium helped leaf retention to the extent of 10 per cent . None of the treatments tried could induce roots in the in vitro shoots. Profuse callusing could be induced from leaf and stem segments in MS basal medium supplemented with growth regulators BA+2,4-D, with a callus index ranging from 280 to 360. The calli did not respond to organogenesis. Callus mass consisted of uniform cells without any vascular differentiation . The morphology and growth rate varied according to the growth regulator combinations tried. Stray instances of embryogenesis (6 to 20%) were observed when cultured in growth regulator combinations of BA+NAA, BA+IAA and Kin+2, 4-D. The embryoids developed up to torpedo stage and failed to grow further. They exhibited a strong callusing tendancy and got reverted to the callus stage within 5 days. The results of the study would be a pioneering report that unravels the in vitro response of ‘Gurmar’ for micro propagation. Since the plant exhibited a relatively recalcitrant nature at various stages of in vitro culture , much more concerted efforts are to be made for standardizing the protocol for micropropagation of Gymnema sylve estre.ThesisItem Open Access Germplasm evaluation in horse gram (Dolichor biflorus. L.)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1993) Swapna, M; KAU; Achamma, OommenA study was undertaken in the Department of Agricultural Botany, College of Horticulture, Vellanikkara during October 1992 to February, 1993 to assess the variability existing in a population of 50 genotypes of horse gram. Evaluations based on the physiological parameters were also carried out. The results revealed the presence of sufficient genetic variability in the different genotypes studied, which were of different geographical origin. High heritability and genetic advance exhibited by the characters, length of pods and number of pods per plant point towards the possibility of these traits to be improved by direct selection. Environmental effect was found to be comparatively higher for yield and number of seeds per pod. Correlation studies indicated maximum correlation of yield with number of seeds per pod and number of pods per plant. Association studies among the different traits showed positive significant correlations between the character pairs, plant height and length of pods, number of primary branches and number of pods per plant, days to 50 per cent flowering and days to maturity; length of pods and number of seeds per pod and 100 seed weight and days to maturity. Divergence analysis gave eleven clusters of which, cluster II and VI showed maximum distance of the cluster members from cluster centroids. The members of these two clusters could be considered superior as parents, for hybridization programme. The maximum mean value for yield was exhibited by members of cluster II. The maximum contribution towards genetic divergence was made by the character 100 seed weight. Growth analysis based as physiological parameters like dry matter production, NAR, CGR, LAI and HI suggested that an ideal plant type will be one in which maximum dry matter production, net assimilation rate and leaf area index was observed during the middle growth stage. An efficient partitioning of dry matter towards the reproductive parts was also an essential criterian.ThesisItem Open Access Pollination studies in cashew(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1985) Elsy, C R; KAU; Narayanan Namboodiri, K MInvestigation on the various aspects of pollination viz., flower opening, fruit set and fruit drop under natural pollination and assisted pollination, effect of pollinating agents and intensity of pollen in the atmosphere were undertaken at the Cashew Research station, Madakkathara and Department of Agricultural Botany, College of Horticulture, Vellanikkara during 1983-84, on six year old BLA-139/1 trees (air layers) under uniform cultural and manurial conditions. The data were subjected to various statistical analysis. The results have shown that the period of flower opening in both male and hermaphrodite flowers was same, starting after 23 hr and extending upto 15 hr next day. The peak period of flower opening for male flowers was between 7 and 9 hr and for hermaphrodite flowers between 9 and 11 hr. Climatic factors such as temperature, sunshine hours, relative humidity and wind velocity have not shown any significant influence on the magnitude of flower opening. Type BLA-139/1 has a relatively low sex-ratio of 1: 2. 83 resulting a higher percentage of hermaphrodite flowers. There is variation in sex-ratio even within the panicles of the same tree. When compared to natural pollination, assisted pollination resulted in significantly higher initial fruit set indicating the inefficiency or inadequacy of pollinating agents. But the higher initial fruit set was not fully reflected in the percentage of fruits harvested since a major portion of the set fruits dropped at different stages of development. In both cases of natural and hand pollination, fruit droop was more in early stages of nut development. This necessitates the need for improving the initial fruit set and more over reducing post fertilization drop for higher yields in cashew. In completely bagged panicles no fruit was set, confirming the cross pollinated nature of cashew. The failure of fruit set in water sprayed panicles rules out the possibility of water as a pollinating agent. Wind plays a significant role in cashew pollination along with insects like red and black ants, honey bees and butterflies which frequently visit cashew inflorescence. The intensity of pollen grains on the atmosphere was 20 times higher than that of hermaphrodite flowers in a unit area.ThesisItem Open Access Genomic relationship in vigna species(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1986) Neema, V P; KAU; Narayanan Namboodiri, K MInvestigations on the genomic relationship in Vigna species were undertaken in the Department of Agricultural Botany, College of Horticulture during 1983-1985. Pure seeds of the two subspecies of Vigna unguiculata, viz. unguiculata and sesguipedalis were sown and crop raised. Direct and reciprocal crosses were made. Morphological and cytological investigations were done. It was found that the two subspecies easily crossable. In both the subspecies there was high prefertilisation shed. The chromosome number of subsp. unguiculata was 2n=22, of subsp. sesguipedalis 2n=24 and of F1 hybrid was 2n= 23. Both the parents and hybrid showed cells with laggards. Length of meiotic and somatic metaphase chromosomes was more in subsp. sesguipedalis, lowest in subsp. unguiculata and intermediate in their F1 hybrid. Both the subspecies and their hybrid had almost similar TF % which gave an indication of similarity in their karyotypes. Pollen fertility was more in subsp. sesguipedalis. Reciprocal difference was seen in the case of morphological characters like height of the plant, number of primary branches, internodal length, seeds per pod, seed colour and seed volume. However, these differences were not seen traceable in the cytology of the hybrid.ThesisItem Open Access Variability studies on certain T X CDO F, hybrids of coconut (Cocos nucifera L)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1987) Sreelatha, P C; KAU; Kumaran, KInvestigations conducted on variability in 14 F1 parental combinations of T X CDO coconut hybrids at the KADP farm attached to the College of Horticulture, Vellanikkara revealed no significant difference between pollen parents in their contribution to the progenies in any of the 17 characters studied, unlike the female parents. The number of spadices was found to be highly correlated with the number of buttons set followed by the number of functional leaves and number of female flowers produced. The fourteen parental combinations were grouped into three clusters using Mahalanobis’ D2 analysis. Clusters I and II were the most divergent ones. Production of spadices and female flowers were found to be high during March, April and May and absent during October, November and December. Heavy rain during active female phase was found to affect setting of button adversely. Fertility and viability of pollen were found to be very high except during April and May due to high temperature.ThesisItem Open Access Genetic variability and correlation studies in cocoa (Theobroma cacae L.)(Department of Agricultural Botany, College of Horticulture, Vellanikkara, 1983) Gregory Zachariah; KAU; Kumaran, KInvestigation on the generic variability and correlation studies in cocoa were undertaken in the Department of Agricultural Botany, College of Horticulture, Vellanikkara during the period from July 1980 to August 1981 in a well established cocoa garden at Alpara in Trichur district, to elucidate information on the extent of variability and the degree of association existing among the 26 important plant, pod and bean characters, in a group of 135 cocoa tress, variety Forastero. Considerable variability was noted among all the characters of the sexually reproduced population of cocoa trees. Number of flowers per unit length on the trunk, number of pods per tree per year, weight of pod, volume of pod and wet weight of beans per pod showed maximum variability. Shell percentage and seed index manifested considerable variability among the bean characters. Phenotypic coefficient of variation (P.C.V.), genotypic coefficient of variation (G.C.V.) and heritability were estimated for 7 pod and bean characters. Both (P.C.V.) and (G.C.V.) were highest for attributes such as thickness of pod husk, number of beans per pod and weight of pod. Moderately high heritability was observed for weight of pod, thickness of pod husk and number of germinated beans. Volume of beans showed the lowest heritability. Yield from trees was found to be positively correlated with 6 of the characters studied, while number of germinated beans per pod and pod value were negatively correlated with yield. Out of the eight characters, pod value had the maximum contribution to yield. Number of pods per tree per year was found strongly associated with yield. Seed index and trunk girth also were positively and significantly correlated with yield. Phenotypic (rp) correlations among seven characters indicated that number of beans per pod was positively correlated with weight of pod. Positive correlations were also established between volume of beans and wet weight of beans per pod. Among the seven characters observed for genetypic (rg) correlations, wet weight of beans showed positive correlation with diameter of the pod and pod weight. Positive phenotypic as well as genotypic correlations were established in the case of wet weight of beans per pod with number of beans per pod and volume of beans. Number of beans per pod in turn, showed positive correlation with weight of pod at both levels. From the present studies it was evident that characters like diameter of pod, wet weight of beans per pod, number of beans per pod, number of germinated beans per pod, volume of pod, volume of bean, pod value, number of cushions on trunk, trunk girth, number of pods per tree per year and seed index have direct influence on the yield of cocoa. These traits can be considered while selecting cocoa trees for using in breeding programmes.
