Kerala Agricultural University, Thrissur

The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively. Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively. On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs. In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc. During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU). Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.

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Open Access
Influence of leaders in the development of rural areas
(Department Of Agricultural Extension, College Of Agriculture, Vellayani, 1981) Shilaja, S; KAU; Tampi, A M
Open Access
Investigations on intervarietal F2 hybrids in cowpea
(Department of Agricultural Botany, College of Horticulture Vellanikkara, Trichur, 1981) Sumathikutty Amma, B; KAU; Narayanan Namboodiri, K M
Ccwpea (Vlgna ungiculata) Is the major pulse crop cultivated in Kerala where the average yield of pulses in general and Cowpea in particular is very low even under modern agronomic practices* This low productivity is mainly due to the absence of high yielding varieties suited for the different agro-climatic conditions. The varietal requirements in Cowpea, in the state vary because of the highly contrasting system of cultivation and this compels Cowpea breeders to evolve varieties of different combinations of plant, pod and seed characters, This is possible by producing different varieties combining the desirable attributes required for the diverse situations by suitable means. One of the ways by which, this can be achieved is through combination breeding in which desirable genes are pooled frcra different sources* In a previous study conducted in the Department of Agricultural Botany, the 202 genotypes v/ere grouped into 17 distinct clusters. Representing 15 clusters, 15 varieties were chosen for intervarietal hybridisation and their F^'s evaluated during 1979-80, Seeds collected from the plants of the 16 Intervariota] crosses along with their parents were used for the study. Two families In each of the 16 crosses were studied along with their respective parents for the pattern of inheritance of 15 economic characters. Most of the characters were found to be inherited as quantitative characters controlled by either polygenes or by a few major genes with their action being suitably modified by minor genes. The crosses 5 x 15 (g p .p l s . 139 x p .118) and 6 X 8 (Red Seeded Selection X Kolingipayar) were identified as suitable ones for grain - production and also for using as dual purpose Cowpea culture since they might throw segregants best suited to those purposes. For the specialised system of Cot/pea culture practised in summer rice fallows exclusively for vegetable purpose, the crosses 14 X 16 (Pannithodan-early X Kolingipayarwhite), 17 X 16 (Mancheri-black X Kolingipayar^hite) and 10 X 6 (IC. 20729 X Red Seeded Selection) appeared to be the Ideal ones*
Open Access
Pattern of growth in domestic fowl
(Department of Statistics, College of Veterinary,Mannuthy, 1981) Jacob Thomas, M; KAU; Surendran, P U
Under uniform feed formula and identical management practices, 30 Australorp (ALP) males, 26 (ALP) females, 25 white Leghorn(WL) males and 31 (WL) females, were reared for 24 weeks in Kerala Agricultural University Poultry Farm, Mannuthy to study their growth patterns. The initial mean body weights of chicks were 35g. for ALPmales, 34.4615g. for ALP females, 33.04g for WL males, 32.0645g. for WL females. Throughout the experiment males in each genetic group had a higher mean weight than females. A plateau on the body weight was reached by the end of 23 weeks in almost all birds, indicating that 24 weeks completely covered the growth period. By the end of the experiment the mean body weight was 1858g for ALP males, 1488.4615g. for ALP females, 1556.8g. for WL males, 1306.1290g for WL females. Though there was no significant difference between the groups at the end of the fourth week, significant differences between pairs were observed after 16 weeks. Exponential (y =aebx), Gompertz (y = abcx) and Logestic (105/y = a + bcx) curves were found to be suitable for fitting body weights for 24 weeks. The first two gave extremely good fit. Modified exponential was good only for data of twelve weeks. When growth rates for twenty four weeks were compared on the basis of the fitted curves for all birds the conclusion arrived at was the same for exponential and Gompertz curves. The rates of growth for ALP males, WL males, ALP females WL females and were in the descending order of magnitude; they were significantly different. Same was the inference obtained when Rao’s method of comparing rates of growth was adopted. The result obtained for comparing the rates of growth by fitting Exponential and Modified exponential for the body weights of birds for 12 weeks were similar. Both the curves gave very satisfactory fit to the data. The coefficient of correlation between the observed and expected body weights was nearly unity in almost all cases.
Open Access
Economics of banana cultivation in Trichur district
(Department of Agricultural Economics, College of Horticulture, Vellanikkara, 1983) Indira Devi, P; KAU; Mukandan, K
This investigation on economics of banana cultivation in Trichur district was conducted during 1983.The study confined to irrigated nendran banana in Chalakudy block with the following objectives viz. to estimate cost and returns; to evaluate resource use efficiency in production; and to study the problems of banana growers. Ninetyeight holdings were selected by following the stratified two stage random sampling technique and the information was collected using a pretested schedule, through personal interview. The total cost of cultivation (cost C) of banana worked out to Rs.41814.13 per hectare. Of this, the most important item of expenditure was human labour. Average labour requirement for banana cultivation was 702.96 mandays per hectare. This was followed by expenditure on manures, fertilizers, propping materials, suckers and irrigation. All of the farmers in the locality applied chemical fertilizers though not upto the recommened level. Plant protection expenses were only 0.30 per cent of total cost. In the operationwise expenditure, manures and manuring operations demanded highest investment and formed 42.50 per cent of total cost. Propping, planting, after cultivation and irrigation, harvesting and handling and preparatory cultivation in that order were the other operations which needed investment. Plant protection operations accounted for 0.92 per cent of total cost. The average returns from banana cultivation were Rs.65011.90 per hectare. The net income from banana cultivation was Rs.23,197.77 per hectare with a benefit cost ratio of 1.55. On a per plant basis, the average cost of producing a bunch was Rs.14.31 and it gave a return of Rs.26. In the linear production function model fitted, plant population and expenditure on labour were the factors which had significant influence on the dependent variable viz. total returns. The former had a positive influence and for the latter the influence was negative. The same model was fitted for the data converted to a per plant basis. The analysis revealed that the farmers were using labour over and above the optimum level. So its use has to be restricted.
Open Access
Impact of the coconut rehabilation programme of SADU in Trivandrum district
(Department of Agricultural Economics, College of Horticulture, Vellanikkara, 1984) Lekshmi Narayanan Nair, N; KAU; Radhakrishnan, V
This study was conducted in 1983 to assess the impact of the Coconut Rehabilitation Programme implemented in Trivandrum District as part of the World Bank assisted, Kerala Agricultural Development project. The specific objectives were to examine the extent of utilization of loans, the improvements in cropping pattern and farming practices, changes in yield rates and output and the increase in farm income generated by this programme. The relative efficiency of irrigation and the various intercrops in augmenting the net farm incomes of the participating farmers was compared and the major constraints in improving coconut farming in the district were also identified as a part of this study. Data were collected from a sample of 96 participating farmers selected at random from the 14 Package Units functioning in the district under this project through personal interview using a well structured schedule. The main findings of the study are summarized below. Majority of the holdings (51.03 per cent) were in the category of less than 0.80 hectare but they accounted for only 27.36 per cent of the area covered. Holdings of 0.80 hectare and above predominated (59.26 per cent) in the category of irrigated holdings. About 49 per cent of the households depended on non-agricultural pursuits for their main source of income. Eighty per cent of the families were relatively small in size with a membership of less than 7. The overall average investment estimated, sanctioned and spent per hectare for the 96 holdings under study worked out to Rs. 17923.05, Rs.14393.67 and Rs.14959.57 respectively. Though the overall performance in respect of loan utilization was satisfactory, there was shortfall in utilization of loans under Cocoa (58 per cent), coconut gapfilling (41 per cent), purchase of Cows (23 per cent) and Fodder Development (17 per cent). The percentage of utilization of loans in the case of unirrigated category was low (50.18) compared to the irrigated category (122.43). Among the lending institutions through which the National Bank for Agriculture and Rural Development funds were channelised, Primary Co-operative Land Mortgage Bank was the most acceptable agency (61 per cent). The cropping intensity of the sample increased from 111.77 per cent to 189.87 per cent consequent on the implementation of the programme. The area under coconut, banana, cocoa and fodder increased while that under tapioca decreased. The density of coconut palms increased from 125 palms per hectare to 176 palms. This is against the project objective of attaining an optimum stand of 175 healthy and high-yielding coconut palms. By and large the target set for intercropping programme as per the individual farm production plans has been achieved. The target was exceeded in respect of banana (119.3 per cent) coconut (103.34 per cent) and cocoa (101.2 per cent). Tapioca continued to be the intercrop widely preferred by the coconut growers (192.75 per cent). Shortfall was mainly in the coverage of area under fodder (18 per cent) and livestock to be purchased (36 per cent). The project has been instrumental in stepping up substantially the level of use of various inputs including irrigation. Fifty four holdings had the benefit of irrigation covering 62 per cent of the net area covered by the sample, while in 13 cases though irrigated development was contemplated, it had not been successful due to operational constraints such as failure to obtain electric connection, failure of wells etc. The average cost of a pumpset with accessories worked out to Rs. 8717.68 while the average amount sanctioned under the lending programme was only Rs.7715 per pumpset. The intensity of senile and uneconomic palms as revealed by the study was only 3.6 palm per hectare against the projection of 20 palms per hectare assumed in the project report. Out of 388 palms identified for cutting and removal only 77 were actually removed. Though the target in respect of gap filling has been exceeded by planting 4790 seedlings against the target of 4762 seedlings, the maintenance of the seedlings was not upto the standard. The increase in use of organic manure for coconut from 17 to 48 kg per palm is commendable. But the use of organic manure for the intercrops is deplorably low especially for banana (6 kg per plant) cocoa (3 kg per plant) fodder (2200 kg per hectare) and tapioca (3698 kg per hectare). Fertilizer application for coconut has increased from 0.22 kg to 1.52 kg per palm. The average fertilizer dose of 0.08 kg per cocoa plant 0.25 kg per banana plant, 33 kg per hectare for fodder and 113 kg per hectare for tapioca as adopted by the participants were also inadequate. Only 6 out of 96 holdings covered under the survey have adopted plant protection measures. The intensity of cultural practices has increased many fold with the biggest increase for coconut (562 per cent). All the crops except tapioca have registered substantial increase in total production. Banana, coconut and milk production registered increases of 677 per cent, 62.45 per cent and 15 per cent respectively. Production of tapioca declined by 25.6 per cent. The increase in productivity of coconut was only 38 per cent over the productivity at the pre-project level. In absolute terms the productivity of coconut has increased from 25 nuts to 30 nuts per palm in the unirrigated holdings while the increase in irrigated holdings was from 30 nuts to 44 nuts per palm. The overall increase was from 29 to 40 nuts for the sample as a whole. The increase in yield was highest in the holdings which have completed 5 years (67 per cent) of development followed by holdings completing 4 years (31 per cent) and 3 years (29 per cent). The post project average yield of intercrops such as cocoa (Rs.59 per hectare) banana (6.95 kg per plant) fodder (4525 kg per hectare) and tapioca (5055 kg per hectare) was considerably low. The average gross income per holding increased from Rs.4478 to Rs.9224. In per hectare terms the increase was from Rs.4613 to Rs.9502 (105 per cent). The average net farm income rose from Rs.2860 to Rs.3821 per hectare (34 per cent). The increase in net farm income was maximum in the case of holdings which had completed 5 years of development (69 per cent) followed by holdings completing 4 years (32 per cent) and 3 years (20 per cent). An increase of 47 per cent in the average yield of coconut, 62 per cent in fodder, 0.47 per cent in banana, 134 per cent in cocoa and 17 per cent in milk was notices under the irrigated holdings over the unirrigated holdings. Comparative analysis of the different intercrops indicated that banana is the most profitable intercrop in coconut gardens in Trivandrum district with a potential net return of Rs.6015 per hectare. Mixed farming with dairying as one of the components, though successful in holdings of more than 0.8 hectare size, ranks only second in order of profitability, with a net income of Rs.2990 per hectare. Tapioca with an average return of Rs.621 per hectare ranks third in the order of profitability. Cocoa, the fourth intercrop compared showed negative returns at the yield and price levels prevailed. Economic uplift of the coconut growers by augmenting farm income through whole farm development approach had been the basic objective of the project. On the whole the project has made a good beginning in this direction in spite of several operational constraints.
Open Access
Effect of growth regulators on flowering pollination and seed-set in ginger(zingiber officinale, rose)
(Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 1984) Usha, K; KAU; Balakrishnan, S
Flowering behaviour and floral biology of Rio-de-Janeiro and Maran and the effect of growth regulators viz., kinetin (5, 10 and 15 ppm), Ethrel (25, 50 and 100 ppm) and NAA (10, 25 and 50 ppm) in combination with two per cent urea and without urea on flowering, pollination and seed-set in Rio-de-Janeiro were studied at the College of Horticulture, Kerala Agricultural university, Vellanikkara during 1981-’83. The objective of the investigation was to assess the available varieties of ginger for flowering behaviour and to evaluate the effect of growth regulators with and without urea on the flowering behaviour, floral biology, floral structure, pollination and seed- set in Rio-de-Janeiro. (The possibility of overcoming the problems of shy and irregular flowering, poor pollen germination and the failure to set seeds also was explored during the investigation). (Among the 25 varieties studied, flowering was observed only in two varieties viz., Rio-de-Janeiro and Maran). Considerable variation was noticed between Rio-de-Janeiro and Maran with respect to flowering behaviour, extent of flowering, types of inflorescence, time taken for scape development, anthesis, anther dehiscence, pollen production, pollen fertility, style length and ovary length. Long but thin style was noticed both in Rio-de-Janero and Maran. Irrespective of the variety, flowers were found to rot/ and dry within 16 hours after flower opening. The maximum pollen germination (6.20 per cent) was obtained in the medium containing eight per cent sucrose, three per cent gelatin and 60 ppm boric acid under moist cotton covering in BOD incubator (26.50C). Coiling of the pollen tube during the advanced stages of growth was noticed. Pollination carried out in Rio-de-Janeiro and Maran employing the variables like stage of flower (bud stage, immediately after flower opening and three hours after flower opening), condition of stigma (partial and complete removal of style), density of pollen (smearing once, twice and thrice with standard brush), mixed pollen (ginger pollen with either Alpinia, Hedychium, Kaempheria or Costus pollen) and supplementary pollination (repeated pollination twice at two hours interval) failed to record any positive evidence of seed-set. Effect of growth regulators and urea on flowering behaviour, inflorescence characteristics and floral structures of ginger was evidenced during the study. ( Favourable influence of NAA 50 ppm on inducing early flowering, kinetin 15 ppm on the duration of flowering, NAA and kinetin on inflorescence production, NAA 50 ppm without urea on the number of flowers per inflorescence, NAA 10 ppm and all the three levels of kinetin on pollen production, NAA on pollen diameter, higher levels of Kinetin and Ethrel and lower levels of NAA on exine thinning, Ethrel 25 ppm in combination with urea, Kinetin 15 ppm with urea, NAA 50 ppm and Kinetin 10 ppm on pollen fertility, lower levels of Kinetin and Ethrel on reducing the style length, Kinetin 15 ppm and NAA 10 ppm on ovary length, Ethrel 25 ppm with urea and higher levels of NAA and Kinetin on pollen germination and NAA 50 ppm on pollen tube growth was revealed during the study.) Floral biology of Rio-de-Janeiro was not influenced by growth regulator and urea treatments. Abnormal floral structures occurred as isolated cases and therefore the role of growth regulators and urea in this respect was not clear from the results. (Pollination carried out in ginger (var.Rio-de-Janeiro) plants, subjected to growth regulator treatments with and without urea, employing the variables like stage of flower, condition of stigma, density of pollen, mixed pollen and supplementary pollination failed to result in seed-set.)
Open Access
Varietal screening of banana against anthracnose disease
(Department of Plant Pathology, College of Horticulture, Vellanikkara, 1984) Srinagesh, K L; KAU; Jose, P C
Laboratory and field studies of the varietal screening of banana against anthracnose disease were conducted at the college of Horticulture. Vellanikkara and at Banana Research Station, Kannara respectively during 1981-1983. In the field the infection started at the distal end of the banana fruit and in course of time the infected fruit became blackened, shriveled and mummified. After Harvest, the symptoms appeared as small brown spots which enlarged quickly and coalesced forming larger patches. The affected areas were covered with orange to salmon pink coloured conidial masses. The detailed morphological studies of the fungus proved that the anthraemose disease of banana is caused by colletrichum cloeosporioides cooko and massee, the imperfect stage of glomerella cinoulata spauld and shrenk. Twenty five varieties of banana fruit were screened in vitro at different stages of development against anthracnose disease. The varieties showed different degrees of susceptibility at various developmental stages of the fruit. The pooled analysis of the data showed that the variety nendra padaththi followed by palayankodan, jurmani kunthali, boodida bontha bathes, peyan, kanchikela, pisang mas and kapok were found to be highly resistant. The varieties Zanzibar, adakka kunnan, klue teparod, chinia, nendran, venneettu mannan, koduppilla kunnan, hybrid sawai, poocha kunnan, red banana and boodles altafort were found to be resistant to the disease. The variety robusta was found to be susceptible. The varieties njalipoovan, pisang lilin, dwarf Cavendish, matti and gros Michel were found to be highly susceptible. The major chemical constituents of banana fruit viz. reducing sugars, total sugars starch, crude fibre, crude protein and tannin at different developmental stages of twenty five varieties were analysed. The reducing sugars and total sugar were found to increase steadily from immediately after female phase to ripened stage in all the varieties. The starch and crude fibre contents, though increased steadily upto full maturity. Declined sharply at the ripening stage. The crude protein and tannin contents were maximum at immediately after female phase but steadily decreased and were minimum at ripening phase. There was a significant positive correlation between reducing sugars, total sugars and per cent disease intensity at three fourth maturity. High sugars were responsible for susceptibility to the disease. A significant negative correlation was obtained between crude protein and per cent disease intensity at half maturity. A significant negative correlation was also obtained between tannin and per cent disease intensity at one fourth and half maturity stages. High crude protein and high tannin contents were responsible for resistance to the disease.
Open Access
Effect of growth regulators and certain formulations on bunch development in banana var. palayankodan
(Department of Pomology & Floriculture and Landscaping, College of Horticulture, Vellanikkara, 1983) Rajendran, P; KAU; Aravindakshan, M
The yield of banana in Kerala remains very low inspite of the adoption of proper manuring and other management practices. Investigations have indicated that the main barrier to the increased production in banana is the lack of sufficient leaf area at the active phase of growth of the plants. The present experiment was conducted with the banana cultivar ‘Palayankodan’ under sparsely irrigated conditions with a view to increase the plant growth and ultimate yield by the use of growth regulators and commercially available formulations. The growth regulators viz., 2-4-D and NAA and the commercially available formulation namely ‘Navras Banana Special’ were tried at four different concentrations as given below:- 2,4-D - 5,10,15 and 20 ppm NAA - 20, 30,40 and 50 ppm ‘Navras’ - 0.25, 0.50,0.75 and 1.00 per cent The various chemicals at different concentrations were applied as two foliar sprays at three and four months after planting. A third spray was also given on the bunches immediately after the female phase of flower opening. On an overall analysis, 2,4-D at 20 ppm and ‘Navras’ at 0.50 per cent were found to be more effective in promoting the vegetative growth of plants. With respect to flowering and duration of the crop, the growth regulators alone had significant effects when compared to the commercial preparation ‘Navras’. The effectiveness also depended on the concentrations of the growth regulators. Thus 2,4-D at 20 ppm induced early shooting of plants by about 12 days whereas NAA at 50 ppm caused substantial delay in shooting. The chemicals at their various concentrations were not effective in influencing the bunch maturity, thus indicating that the applied chemicals caused the earliness or delay observed, through their influencedon the vegetative growth only. Consequent to the application of 2,4-D at 20 ppm the crop duration was advanced by 22 days. Contrary to this, NAA at 50 ppm delayed the duration of the crop. The treatments with 2,4-D at 5 to 20 ppm, NAA at 40 and 50 ppm and ‘Navras’ at 1.00 per cent were found to advance the ripening of fruits. The best quality fruits in terms of TSS and total sugars were obtained by the application of 2,4-D at 20 ppm. Among the concentrations of ‘Navras Banana Special’, o.5 per cent gave the best results with respect to the growth and yield of plants. When the concentration was increased further, there was a decrease in the performance of the plants. The optimum doze of ‘Narvas Banana Special’ was worked out to 0.534 per cent. The correlations worked out from the data collected revealed that the vegetative and bunch characters such as girth of psuedostem, number of functional leaves, total leaf area, length of bunch, number of hands and fingers per bunch, number of fingers per hand and weight of hand, length, girth and weight of fingers amply contributed to the overall yield in the form of bunch weight. The yield increase observed in the present study due to the application of 2,4-D at 20 ppm was by 88 per cent and that for ‘Navras’ at 0.5 per cent was by 96 per cent. The benefit/cost ratio worked out for these treatments did not differ and hence application of 2,4-D (20 ppm) and ‘Navras Banana Special’ (0.5 per cent) were equally good for increasing the yield. The present investigations were conducted under sparsely irrigated conditions where, irrigation was given just for the maintence of the crop. Further investigations with rainfed and irrigated ‘Palayankodan’ bananas may be of particular interest.
Open Access
Relative susceptibility of cashew types to infestation by the tea mosquito helopoltis antonii signoret (hemiptera:miridae)
(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1981) Thomas, K M; KAU; Abraham, C C
The relative susceptibility of fourteen cashew accessions (Anacardium occidentale L.) to infestation by the tea mosquito bug Helopeltis antonii signoret (miridae: HEmiptera ) was evaluated in the field experiments conducted at the Cashew Research Station , Madakathara during September 1979-March1980. The field damage Intensites and the extent of damage Inflicted by the insect consequent on confinement on shoots and panicles were recored on a 0-5 scale and it was found that the accessions 22,1112, 1430 and 1097 were least susceptible with regard to the intensity of natural field infestation of the vegetative shoots. Regarding the intensity of field infestation on floral branches, the accessions, 22, 1112,1352,1469 and 1097 were significantly less susceptible than the other types . With reference to the intensity of damage to vegetative shoots under confinement none of the accessions was found to be promising . The accession numbers 1219 , 1469 and 1431 were found to be least susceptible to H. antonii infestation under confinement on floral branches . Since the damage to the floral branches, particularly under confinement , Is relatively more important factor responsible for yield reduction these trees can be identified to be relatively more promising . The influence of certain biochemical factors (total nitrogen , soluable sugar and tannins ) on pest infestation in shoots and floral branches was ascertained by working out simple correlation coefficients. The only significant association detected was between the tannin content in the vegetative shoots on the one hand and the pest infestation intensities under confinement , on the other. The shade intensities within the canopies had no the extent of susceptibility to the pest. The tree architecture patterns were found to be of two basic types, namely, extensively branching (spreading ) and intensively branching (bushy ). Variations in the canopy configuration did not influence the susceptibility trends. The inconsistencies in the relative susceptibility of different accession with reference to shoot and panicle damage intensities have been discussed.

Kerala Agricultural University, Thrissur

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