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ThesisItem Open Access Studies on fertility status of rubber growing soils of Palakkad district(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1991) Mohanan, V; KAU; Nazeem, P AThesisItem Open Access Heterosis in snakegourd (Trichosanthes anguina L.)(Department of Olericulture, College of Horticulture, Vellanikkara, 1991) Philip Varghese; KAU; Rajan, SThe present investigation "Heterosis in snakegourd" was conducted at the College of Horticulture during 1988-1990. Assessment of genetic variability showed significant differences of 25 characters in 48 snakegourd genotypes. The highest phenotypic coefficient of variation was observed for fruiting nodes on main vine, male flowers/plant, sex ratio and fruits/plant. The pcv was lowest for total crop duration. The gcv resulting in high heritability was high for majority of the characters. High heritability coupled with high genetic gain was noticed for male flowers/plant, sex ratio and fruiting nodes on main vine. The 48 genotypes were grouped into 10 clusters. The combing ability analysis revealed significant gca variances for all characters. The sca variances were also significant for all characters. The sca variances were also significant for all characters except for total crop duration, sex ratio and fruits/plant.ThesisItem Open Access Evaluation of F1 hybrids resistant to bacterial wilt and inheritance of resistance in brinjal (Solanum melongena L.)(Department of Olericulture, College of horticulture, Vellanikkara, 1991) Geetha, Varghese; KAU; Abdul Vahab, MThe present studies "Evaluation of F hybrids resistant to bacterial wilt and inheritance of resistance in brinjal (Solanum melongena L.) were conducted during February 1990 to July 1991 in the vegetable research plots of Kerala Agricultural University, Vellanikkara. Evaluation of F1 hybrids over 4 environments revealed that all the 3 hybrids were superior to their parents for yield during all the four seasons. It also indicated significant role of genotype x environment interaction in the yielding ability of the hybrids. Considering wilt resistance the hybrids were not superior to their parents. Varietal difference was observed for plant height, fruits/ plant, fruit weight, fruiting period and productive flowers. Estimation of heterosis of three F1s over their parents revealed significant heterosis for plant height, days to flower, days to first fruitset, days to harvest, primary branches/plant, total fruits/plant, total yield/plant, average fruit weight and fruiting period. All the three hybrids viz. Surya x Pant Rituraj, SM 6-6 x SM 132, SM 6-2 x Pusa Purple Cluster were stable. Study on the nature of inheritance showed that resistance to bacterial wilt is inherited in a recessive and monogenic manner.ThesisItem Open Access Standardisation of in vitro propagation technique in banana(Department of Pomology & Floriculture, College of Horticulture, Vellanikkara, 1991) Jyothi Bhaskar; KAU; Aravindhakshan, MInvestigations were carried out at the Plant Tissue Culture Laboratory of the College- of Horticulture, Vellanikkara during 1988-90 to standardise the in vitro propagation technique in banana. Three banana cultivars namely Nendran (AAB) , Palayankodan (AAB) and Red banana (AAA) were utilised for the study. For standardising the explant, three types of explants were used namely shoot tip , eye bud and floral apex. For culture establishment, axillary shoot initiation and in vitro rooting studies different types of growth regulators were made use of. They were auxins (NAA, IAA and IBA) , gibberellin (GA) and cytokinins (BA andkinetin) . The plantlets produced _in vitro were subjected to different types of hardening treatments to secure a better establishment of planted out plants For shoot tip and eye bud explants, surface sterilization using mercuric chloride (0.2 per cent) for 5 min. was' found to be the best, but for floral apex ex plant an initial rinsing of the explants with 95 per cent absolute alcohol for 30s followed by mercuric chloride treatment (0.05 per cent) for 10 min. was found to be best. Better and speedier ex plant establishment and growth of shoot tip, eye bud and floral apex explant was observed in MS (semi-solid) medium containing NAA 0.5 ppm and BA 3.0 ppm Gibberellic acid was found to have unfavourable effect on culture establishment and growth. Shoot tips collected during November to April recorded maximum surviva l percentage. Among the physical injury treatments for enhancing the release of axillary buds in culture splitting the apical dome of shoot tip longitudinally into two halves and culturing each half separately was found to be the best. The addition of ascorbic acid into the media at the rate of 50 mg/1 reduced media and ex plant discolouration due to polyphenol oxidation. When the performance of the three explants w.ere compared', floral apex ex plants took more time for culture establishment. The three banana cultivars used for the study responded differently in culture.ThesisItem Open Access Effect of growth regulators and nutrients on spike qualities of gladiolus(Department of Agronomy, College of Horticulture, Vellanikkara, 1991) Leena Ravidas; KAU; Rajeevan, P KStudies were carried out at the College of Horticulture , Vellanikkara during 1988-89 to examine the effect of growth regulators and nutrients on the growth parameters and spike qualities of five varieties of gladiolus, in two seasons. The treatments significantly influenced all the vegetative characters, duration , most of the spike characters as well as corm and cormel yield in one variety or other. Growth retardants TIBA and CCC and salts of Ca recorded least height. TIBA 300 ppm and CCC 250 ppm produced the maximum number of leaves, followed by GA 100 ppm and salts of Ca and K. In leaf area, K2SO4 causes a significant increase. TIBA 300 ppm, NAA 100 ppm, GA 100 ppm and salts of Ca were the other superior treatments. While K2SO4 and GA 100 ppm reduced the duration till the appearance of flower spike , that from spike emergence to opening was the shortest with salts of Ca and K, in general. GA and Ca(N03 ) 2 lengthened the blooming period , whereas and GA 100 ppm reduced the total duration . In general, K2SO4 0.5%, CaSO4 0.5% and GA 50 ppm were superior in increasing the spike length . Diameter of spike was the maximum with growth inhibitors , in most of the varieties . GA and salts of Ca were also superior. Ga 50 ppm as well assalts of Caa nd K helped in producing the longest rachis . Salts of Ca at 1.0% level and GA produced the highest number of florets . However, the length and size of the florets were not affected by the treatments. CCC, Ca (N03)2 1.0% and KNO3 0.5% recorded the maximum fresh weight of the spike . TIBA 150 ppm , CCC, GA, Ca(NO3) 1.0% and CaSO4 lengthened the vase life . GA, NAA 100 ppm, CCC 500 ppm and Ca(NO3)2 were superior with respect to the opening behaviour of the florets . Longevity of individual floret was improved by GA 100 ppm , K2SO4 and Ca (NO3)2. Salts of K and Ca(NO3)2 1-0% enhanced the number of florets opened at a time . NAA 100 ppm and GA 50 ppm exhibited maximum water uptake. However, the treatments could not influence the nature of bending. NAA, GA and salts of Ca and K increased the corm yield . Number of cormels was mostly affected by the nutrients . K improved the weight of cormels too. In general, floral characters were superior in the varieties American Beauty and Friendship , whereas vase life was the maximum in Agnirekha and Mansoer Red. True Yellow produced heavy corms. Weight of cormels was the maximum in Agnirekha and Mansoer Red. November planting was found to be better than April planting, in order to obtain quality spikes as weII as good cormel yield in gladiolus under Vellanikkara conditions.ThesisItem Open Access Relative response of explant material of Anacardium occidentale L. to in vitro culture(Department of Horticulture, College of Agriculture, Vellayani, 1991) Lawlita, Nair; KAU; Mohanakumaran, NThe task of developing intact plants from tissues of woody plants has been attempted and success reported in a few crop species, mostly with explant tissues such as shoot tips, intermodal region, leaf parts, from seedlings, In vitro methods, if standardised, can facilitate rapid multiplication of, and therefore, expansion of area under high yielding material of crops like cashew. In such an exercise, the selection of explant material assumes utmost importance. The present studies were, therefore, aimed at examining the relative response of different explant materials of cashew to in vitro culture. During the initial period of study, fungal and bacrerial contamination was a major problem, which was reduced to some extent in the further trials, by surface - sterilisation. Among the surface – sterilants used, mercuric chloride gave good results. Contamination was severe with bleaching powder. conditions . Interference of polyphenols was observed during certain stages of the study. The oxidised polyphenols were found to diffuse into the medium. The problem was overcome by including antioxidants (activated charcoal, polyvinyl pyrolidine, ascorbic acid, citric acid and combinations of these) in the media. Murashige and skoog (MS) medium, Schenk & Hildebrandt (SH) medium, Lin and Staba (LS) medium and Woody Plant Medium (WPM), supplemented with growth factors like gibberellic acid (GA), naphthalene acetic acid (NAA), kinetin and 2,4-D were tried. Among the media tested, SH gave better results, followed by MS, LS and WPM. New green buds were found to develop when the culture establishment studies were carried out with MS basal, supplemented with kinetin and NAA at (1 mg/1 + 10-1 mg/1). (1 mg/1 + 0.5 mg/1) and (2 mg/1 + 10-1 mg/1). However, these cultures showed symptoms of drying soon after subculturing. Callus development was observed when shoot tips were cultured in MS + Kinetin + NAA at 2 mg/1 + 1 mg/1, respectively and MS + Kinetin + 2, 4-D at (0.5 mg/1 + 1.0 Mg/1), (1.0 mg/1 + 4.0 mg/1) and (2.0 mg/1 + 1.0 mg/1). Comparatively better results were observed with SH + Kinetin and 2, 4-D. The cultures were hampered with browning which was overcome, to a certain extent, with pre – culture treatments and additives. Percentage survival was fair on pre – culture treatment with ascorbic acid at 150 mg/1, 300 mg/1 and citric acid at 75 mg/1. Callusing was also observed and the rate ranged from fair to good with citric acid at 150 mg/1 and with combination of ascorbic acid and citric acid at 150 mg/1 each. Callusing, ranging from poor to fair, resulted with SH + kinetin and 2, 4-D at (1 mg/1 + 1 mg/1). (1 mg/1 + 2 mg/1) and 2 mg/1 + 4 mg/1), respectively. Survival ranged from 33 to 66 per cent, with Lin and staba medium supplemented with kinetin + NAA and kinetin + 2, 4 – D. The results were same when the basic medium was changed to WPM. The explants were cultured in liquid media. But none of the cultures could give any positive results. Shoot tips were found to be the most responding explant among the many tried in different media. Among the combinations of growth substances tried, kinetin + 2, 4 – D was found to give good results when kinetin was used at a low and 2, 4 – D at a high concentration. Response of cashew explants to in vitro culture can be improved by further modification of the medium and culture conditions.
