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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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ThesisItem Open Access Study on the role of leadership in agricultural development in rural areas in Kerala(Department of Agricultural Extension, College of Agriculture Vellayani, Trivandrum, 1979) Muthiah Manoharan, P; KAU; Thiagarajan Nair, GThis study on the role of leadership in agricultural development was designed to measure the role perception and 1 f role performance of different categories of leaders, as well as the factors associated with the role performance of leaders. This study was conducted in Arayoor I.P.D. Unit in Trivandrum District. This study covered five categories of leaders viz., Agricultural, Political, Co-operative, Ela committee and Panchayat leaders. The important findings were the following: 1. There was no significant difference among all categories of leaders regarding their age, educational level, communication skill, attitude towards agriculture and knowledge of the programme and improved agricultural practices. . 2. Agricultural and Ela committee leaders had higher farm size, higher income and had adopted more practices when compared to other categories of leaders. . 3* Agricultural, Panchayat and Co-operative leaders had high value orientation, high achievement motivation and had more favourable attitude towards high yielding varieties than other categories of leaders. 4. Co-operative leaders had more favourable attitude than other categories of leaders towards fertilizers* Panchayat, Agricultural and Political leaders had more favourable attitude than other categories of leaders towards plant protection. 5. Ela committee leaders had more mass media exposure than other categories of leaders. Ela committee, Agricultural and Panchayat leaders had more frequent contact with extension agency than other categories of leaders. ■ 6. The results revealed that Panchayat and Agricultural leaders had more perception of agricultural development roles than other categories of leaders. Agricultural leaders performed more roles in agricultural development than other categories of leaders. 7. When the pooled ranks were worked out the role "Accept improved agricultural practices before others" emerged as the most important role perceived as well as performed by the leaders. 8. Mass media exposure was significantly correlated with the role performance except in Political leaders. Caste also had influence in role performance. 9. Six variables viz., farm size, income, knowledge, mass media exposure, contact with extension agency and adoption behaviour were correlated, with role performance . significantly when the pooled data were considered. 10. Inter-correlation analysis lead to the conclusion that farm size had significant correlation with income, knowledge, mass media exposure, contact with extension agency and adoption behaviour. Income was significantly correlated with knowledge, mass media exposure, contact with extension agency and adoption behaviour. Knowledge was significantly correlated with contact with extension agency and adoption behaviour. There was also a significant correlation between mass media exposure and contact with extension agency. 11, It was also observed that the proportion of role performance explained by the variables viz., farm size, income, knowledge, mass media exposure, contact with extension agency and adoption behaviour was 50 percent.ThesisItem Open Access Studies on the regulation of progeny production and sex-ratio of Wesmael(Department of Agricultural Entomology, College of Horticulture,Vellanikkara, 1979) Susamma, Jacob; KAU; Abraham, C CThe fecundity, progeny production, female – male composition of the progeny and duration of development of Bracon brevicornis wesmael as influenced by the density and size (weight) of host larvae of Corcvra cephalonica Stainton and the sex-ratio of the parent parasite population were studied at three temperature- humidity (TH) combinations, viz, 280c and 75% RH (TH1), 300c and 60% RH (TH2) and 320c and 50% RH (TH3). The maximum fecundity of the parasite was registered consistently at all the three TH levels at a host density level of two larvae per female parasite. The exclusive use of light weight larvae (weight range 8 to 10 mg) as hosts produced significantly less number of eggs at the TH1 and TH2 levels, while at the TH3 level the fecundity was maximum when the heavier host larvae (weight range 30 to 35 mg) were used. The parental sex-ratio levels of 2:1 and 3:1 (female:male ) led to the production of higher number of eggs than under the ratios of 1:1, 1:2 and 1:3. The maximum progeny production in B. brevicornis at the TH1 and TH2 levels was attained under a host density level of two larvae per female parasite. The progeny production was relatively higher at the TH1 and TH2 levels when heavier larvae were exposed for parasitisation. The superiority of the parental sex-ratio of 2:1 (female: male) in the production of higher number of progeny was established at the TH2 and TH3 conditions. Significant influence of the host larval density on the female progeny production was detected at the TH1 and TH2 levels. The female progeny production was maximum at a host larval density level of two per female parasite at the TH2 combination, while this was found to be the highest at a density level of one larva per female parasite at the TH1 level. Relatively heavier host larvae produced significantly higher number of female offsprings at the TH2 and TH3 combinations. The parental sex-ratio level of 2:1 (female:male) consistently produced maximum number of female progeny. The influence of host larval density on the proportion of females was pronounced only at the TH3 level and a density level of two laevae per female parasite was found to be better with reference to the production of a higher proportion of females. The sex-ratio of the parent parasite population influenced the proportion of females in the F progeny and a ratio of 1:3 (female:male) produced higher proportion of females at the TH2 and TH3 combinations. The host larval density, weight of host larvae and the sex –ratio of the parent parasite population exerted significant influence on the duration of development of B. bravicornis. The feasibility of manipulating the ambient temperature-humidity conditions for maintaining laboratory cultures of B. brevicornis at the maximum possible levels has been discussedThesisItem Open Access Effect of phospherus nutrition liming and rhizobial inculation on soybean(Department of Agronomy, College of Horticulture, Vellanikkara, 1979) Kurian, T M; KAU; Vikraman, RAn experiment was conducted at the Instructional Farm attached to the College of Horticulture, Vellanikkara during July to October 1978, to study the effect of phosphorus nutrition, liming and rhizobial inoculation on soybean (Glycine max (L.) Merril). The investigation was taken up with the objective of arriving at the phosphorus requirement of the crop, assessing the response to liming and evaluating the effect of rhizobial inoculation. The trial was also aimed at studying the possible interaction effects between these factors. The experiment was laid out as a factorial in randomized block design with 16 treatments and 3 replications. The study revealed that applied phosphorus did not significantly affect any of the growth characters consistently. Grain yield and yield attributes were also unaffected but stover yield increased with higher doses of applied phosphorus. In general, nitrogen, phosphorus and calcium contents in plant components were unaffected by levels of phosphorus, liming and rhizobial inoculation. Uptake of these nutrients also remained almost unchanged. At harvest, nitrogen uptake by seeds constituted 44 per cent of the total, remaining being accumulated in stem + petiole and shell. In the case of phosphorus, 86.9 per cent of the total accumulation was in seeds, 6.0 percent and 7.1 per cent being in stem + petiole and shell respectively. Calcium being an immobile nutrient and an element not translocated within the plant, proportion of uptake of calcium in various components of the plant was different from that of nitrogen and phosphorus. In contrast to nitrogen and phosphorus, only 24.9 per cent of the total was found in seeds whereas 36.3 per cent and 38.8 per cent of it were concentrated in stem + petiole and shell respectively. Levels of phosphorus, had no effect on total nitrogen and available potassium contents of soil after harvest of the crop but there was a notable increase in available phosphorus and decrease in exchangeable calcium. Liming and rhizobial inoculation did not have any conspicuous effect on the content of nutrients in soil.ThesisItem Open Access Effect of different growth regulators on flowering and fruit development in pineapple(Department of Horticulture (Pomology), College of Horticulture, Vellanikkara, 1979) Santha, K K; KAU; Aravindakshan, MThe present investigations were carried out in College of Horticulture, Kerala Agricultural University during the years 1976-78. The object of the study was to find out the effect of growth regulators and certain other chemicals on flowering and fruit development in pineapple. The growth regulators and chemicals included in this study consisted of ethrel and Planofix at different concentrations and combination of Ethrel, Ca CO3 and urea. Ca C2 was also included in this study. Seasonal variation in the effect of growth regulators and chemicals in two seasons was noticed. Application of growth regulators and chemicals in January resulted in earlier flowering than November application. The differential response of growth regulators in the two seasons might be attributed to the variation in leaf area. Of the different growth regulators and chemicals tried, Ethrel 250 ppm was found to be the for maximum induction of flowering. Ethrel at all concentrations was found to reduce the duration of flowering and also the time for fruit set. Ethrel in combination with urea 2 per cent and Ca CO3 0.04 per cent also showed similar effect. Time taken for fruit maturity was slightly reduced by Ethrel treatment while it was delayed by the application of Planofix. In respect of fruit size, maximum size was obtained by Planofix 20 ppm. None of the growth regulators, chemicals and combinations tried resulted in an over all improvement in quality of fruits, but the number of leaves possessed by a plant profoundly influenced the quality of fruits. While induction of flowering could be achieved by the application of growth regulators and chemicals irrespective of the morphological characters of the plant, the fruit development was found to be associated with the number of leaves possessed by the plant. The fruits produced by plants with higher number of leaves (Class IV) possessed maximum of TSS, reducing sugars, total sugars and sugar acid ratio closely followed by Class III. For a satisfactory fruit development the plant should possess around 40 leaves at the time of application of growth regulators. The nutrient status of leaves was also found to influence fruit development considerably. The largest fruits were produced by plants having leaf nutrient status of 1.40 per cent N, 0.08 per cent P and 3.43 per cent K. The application of growth regulators and chemicals was responsible for low sucker production. Ethrel at 1250 ppm retarded the sucker production to a maximum extent.ThesisItem Open Access Propagation studies in cocoa(Department of Horticulture (Plantation Crops), College of Horticulture, Vellanikkara, 1979) Kesavachandran, R; KAU; Sivaraman Nair, RA study on the different aspects of propagation of cocoa was undertaken at the College of Horticulture from May 1978 to July 1979 to standardise the criteria for selecting the pods, seeds and seedlings for raising the nursery, to find out the optimum size of polythene bags and the suitable medium for raising the nursery and also to standardise the best vegetative propagation methods for cocoa. The results had indicated that the volume and weight of the pods varied within the three classes of pods namely large, medium and small. There was not much variation in the number of seeds among the three classes of pods and the mean number varied between 30 to 42. The number of seeds were found to be highest in pods harvested in February and March followed by April. The highest percentage of germination was recorded in March followed by February, January, December and April. The size of the pod and the position of seeds (pedicel end, middle and distal end) had no significant influence on the germination and the growth of the seedlings. However, the large and medium sized pods are found to produce better seedlings. Based on the studies the following recommendation are made i) Large and medium sized pods weighing more than 350g each with not less than 400 cc volume should be selected for raising the nursery during the month of February and March. ii) The seed should be sown on the same day of harvest but it can be stored under room conditions upto six days. The percentage of germination will be decreased to 66 per cent by the sixth day. iii) A selection criterion for selecting the seedlings when they are three months old is recommended. The seedlings should have atleast 30cm height and 10 or more number of leaves when they are three months old. For raising three to five month old seedlings, the optimum size of bag is found to be 30 x 20 cm and the best medium for raising cocoa nursery is a mixture soil, sand and farm yard manure in the proportion 1:1:2. Considering the pattern and extent of root and shoot growth of the seedlings, planting the seedling when they are three to four months old is suggested. For higher percentage of rooting and optimum number of roots and higher root length, a ‘quick dip’ method for 60 sec in 4000 ppm NAA or 6000 ppm IAA is recommended for producing rooted cuttings. A ‘mist chamber’ method is suggested for rooting the cuttings. Forkert method of budding is recommended for cocoa either on eight to nine months old root-stocks or by green budding on three to four months old root-stock. The best time for budding is February and March on older root-stocks and April and May for green budding.ThesisItem Open Access Design, development and testing of a transplanting mechanism for conventional paddy seedling(Department of Farm power and Machinery, College of Agricultural Engineering,Ludhiyana, 1979) Cheeram Parambil, Muhammad; KAU; Verma, S RFor over half of the world’s population, rice provides the main dietary source of energy and hence is one of the most important food materials. In the Far – East, where 90 per cent of world’s rice is grown, transplanting is widely practised due to numerous advantages offered by this method. Manual transplanting being a rather tedious operation, paddy transplanters had been developed and introduced in several countries notably Japan. Transplanters using conventional seedlings, however, are still receiving world wide attention as the commercial transplanters such as in use in Japan were costlier and employed special type of nursery raised with much care and skill. It was, therefore, decided to develop and test a new type of paddy transplanting mechanisms, with the following specific objectives: 1. To design and develop a mechanisms for transplanting conventional paddy seedlings 2. To test the transplanting mechanisms under laboratory conditions 3. To identify the important parameters of the mechanism and establish their range for optimal operation of the unit designed under objective (1). Accordingly, a paddy transplanting mechanisms was designed and developed. Attempts were made to overcome, as far as possible, the drawbacks of similar mechanisms already developed and reported. It was a single - row unit with provision to add more such units, as as to make a multi - row machine with a row - spacing of 20 cm. It was designed to transplant washed - root seedlings of 20 to 30 cm length at a hill to hill distances of 15 cm, with 2 to 3 seedlings/hill, to a depth of 3 to 4 cm, with not more than 5 per cent missing hills and 1 per cent seedling damage. Made mainly of M. S. and supported on a wooden float, the mechanism weighted 9.5 kg without seedlings. The important components of the mechanism were a seedling box to hold the seedlings, a seedling rake and seedling ejector for positive conveyance of the seedlings into the picker – jaws, a pair of picker sets mounted on the main shaft and actuated by a stationary cam to pick and release the seedlings, and a planting finger to plant the seedlings, laid horizontally on the ground after release, by the pickers. The main shaft was rotated by a ground wheel, as the mechanism was drawn forward by manual, animal or tractor power. In order to study the effect of reduced tip velocity of the pickers, another mechanism with four picker-sets, based on the same concept as the first one, but with proportionately larger dimensions of pickers and stationary cam, was also fabricated. The components like seedling box, rake, ejector and main shaft were retained with the same specifications as for the mechanism with two picker - sets. This mechanism weighed 11.75 kg against 9.5 kg for the first mechanism. The mechanism with two picker sets was designated as mechanism – A and that with four picker sets as mechanism – B for convenience. The two mechanisms were tested in the laboratory to compare their performance in respect of the plant hill missing, seedling damage, seedling distribution, average number of seedlings per hill and the power consumption. The tests were conducted with 4 rates of picking, i.e. 60, 90, 120 and 150 hills/min and 3 seedling heights i.e. 30, 25 and 20 cm for both mechanism A and B. The laboratory tests revealed that as the rate of picking increased from 60 to 150 hills/min, the missing hills increased from 4.09 to 16.8 per cent and 6.95 to 16.44 per cent; seedling damage from 0.8 to 1.43 per cent and 0.53 to 0.89 per cent; and power consumption from 13.6 to 33.6 and 17.1 to 42.1 watts for mechanisms A and B respectively. The average number of seedlings for both the mechanisms studied, decreased from 2.4 to 2.0 for 30 cm long seedlings as the rate of picking increased from 60 to 150 hills/min. However, upto a picking rate of 120 hills/min, the missing hills were 5.69 and 10.69 per cent for mechanisms A and B respectively, as against the desired 5 per cent missing hills. Seedling damage was less than 1 per cent and average number of seedlings/hill was above 2.00 in both the mechanisms with a variation of 0 to 8 seedlings/hill with a maximum standard deviation of 1.32. As the seedling height was reduced from 30 to 20 cm, the average number of seedlings/hill was found to increase from 2.36 to 2.55 at the rate of picking of 60 hills/min, 2.11 to 2.39 at 90 hills/min, 2.07 to 2.39 at 120 hills/min and 1.99 to 2.09 at 150 hills/min. At all seedling heights, upto 120 hills/min, the average number of seedling/hill was above 2.00, which was within the required limit. On comparing the performance of the two mechanisms, it was found that there was no difference between the two regarding their ability to pick the number of seedlings/hill. However, missing hills were more in mechanism B as compared to mechanism A. For a rate of picking, upto 120 hills/min mechanism A had acceptable missing hill of 5.69 per cent as against the recommended 5 per cent, while mechanism B, had 10.67 per cent which was considerably higher than the acceptable limit. The seedling damage, upto 120 hills/min rate of picking was under 1 per cent for both the mechanisms. Limited field trials revealed that the planting finger provided in the mechanism did not function satisfactorily and as such the plants were not properly planted. Deposition of mud on the stationary cam and seedling ejector was a problem noticed in the field. Consequently, the free rotation of the main shaft was hampered which in turn led to the skidding of the ground wheel. This called for further improvements in the design of the planting finger and groundwheel drive. It was concluded that mechanism A could pick the seedlings from the seedling box and release them satisfactorily on the ground upto a picking rate of 120 hills/min. The missing hills and seedling damage were within acceptable limits. Trouble – free working of the transplanter fitted with such mechanism would have a capacity of about 0.0216 ha/hr per row. The forward speed for the rate of picking viz. 120 hills/min comes to about 1.08 kmph. The mechanism could not plant the seedlings erect and improvement on planting finger was needed. About 125 man – hrs/ha were required to wash and load the seedlings and if a 4-row bullock drawn version could be used, it would require about 140 man-hrs/ha as against 200 to 250 man-hrs/ha in hand transplanting. This would justify further developmental efforts and refinement of the mechanism.ThesisItem Open Access Studies on growth ,flowering ,fruit set and fruit development in nutmeg (Myristica fragrans hout.)(Department of Plantations Crops, College of Horticulture, Vellanikkara, 1979) Nazeem, P A; KAU; Sivaraman Nair, P CThe present investigations were carried out in the College of Horticulture, Kerala Agricultural University during the year 1978-’79. The object was to study the pattern of growth and flowering, floral biology, fruit set, fruit drop and fruit development in nutmeg. The studies were conducted on male and female trees of about 17 years old receiving cultural practices as recommended by Kerala Agricultural University. Shoot growth in nutmeg was found to be cyclic, a period of growth followed by a quiescence. Six flushes were observed during the period of one year. All the flushes were not seen in all the shoots which resulted in continuous growth in nutmeg. The mean growth varied significantly from month to month, with minimum in summer months. Two peaks were observed in May, June and September. Nutmeg trees were found to be slow growers when compared to other prerennial trees. Flowering pattern of male and female trees differed. There was monthly variation in the extent of flowering of both male and female trees. In females, flowering was constrained to seven months whereas in male, flowering was observed through out the year. Maximum flowering in both the cases was in July followed by October. The flower bud development in male and female trees followed specific pattern. The male flowers took only about half the period taken by the female flowers to develop. The female flowers took 154 days for complete development. Three types of flowers were observed in nutmeg which resembled and differed each other for different characters. In male flowers, peak anthesis was between 1900 hours and 0100 hour and in females, it was between 2100 hours and 0300 hours. Anther dehiscence occurred about 24 hours prior to anthesis. The stigmatic receptivity lasted for six days after anthesis with the maximum for the first three days. The chief agent of pollination was wind. Anther number and pollen production per flower varied from tree to tree. Sucrose at concentrations of 2, 4, 6 and 8 per cent, boric acid and calcium nitrate at concentrations of 25, 50, 75 and 100 ppm each were found to promote pollen germination. A combination of the three (4% sucrose, 25 ppm calcium nitrats and 75 ppm boric acid) gave maximum germination (96.9%). Pollen was found to be viable for three days in the dehisced bud condition and the viability was greatly reduced thereafter. The percentage set varied for different trees and for different aspects with maximum set on Western and eastern aspects. Hand pollination increased the percentage set than open pollination, indicating the possibilities of assisted pollination for better production. There was no apomictic fruit development. The mean percentage drop after set was 74.4 per cent. The number of fruits harvested accounted to only 8.47 per cent of the total flowers produced. The period of maximum drop after set coincided with the period of maximum development of the fruit. The fruits attained maturity in 206 to 237 days after fruit set. The developing fruits followed a sigmoid growth pattern. The peak harvest season ranged between April and July. The trees varied for the percentage drop and number of fruits harvested.ThesisItem Open Access Studies of rats and rat traps of Kerala(Department of Agricultural Entomology, College of Horticulture, Vellanikkara, 1979) George, C M; KAU; Joy, P JIn order to study the distribution of different species of rate in the State a detailed survey was conducted in different parts during the period from September 1978 to February 1979. Burrows of the various species were excavated to get detailed information on the special features of the burrow patterns. The findings of the present investigation are summarized below. It was found that 15 species of rats occur in Kerala. 1. Tatera indica cuvieri Of the four subspecies of Tatera indica, only T. indica cuvieri was present in Kerala. This species was distributed all over Kerala except in higher elevations like Wynad. The burrow system followed no specific patterns with a minimum of three openings. The emergency escape were concealed underneath. The burrowed out soil was expelled through a particular opening. More than one adult lived in a burrow system. 2. Rattus norvegicus This was a serious pest of paddy in Idukki district and Kuttanad and was mostly a field rat in Kerala. 3. Bandicota bengalensis bengalensis This species was more predominant in garden lands. Burrow were found extensive. Burrow entrances were concealed by heaps of soil. Food was found stored in the burrow system only in a few cases. Male and female rats lived in separate burrows. 4. Bandicota indica indica A field rat causing great damage to tuber crops. The burrow openings were larger in size than those of other species. The exit for removal of soil was always located on a higher point. Definite runways starting from the entrances were seen. 5. Mus platythrix The burrow openings of this mouse were encircled by pebbles. It lived in discarded burrows of other species of rats and not a fossorial type. 6. Mus saxicola Similar to M. platythrix in every aspect. 7. Mus booduga booduga It lived in small burrows in paddy fields and garden lands. The burrow system was always seen provided with one or more emergency escapes. 8. Mus cervicolor Found similar to M. booduga booduga in appearances, habits and habitats. 9. Mus musculus Found in houses and shops. 10. Rattus rattus Two subspecies were found in Kerala viz., R. rattus ruffescens and R.r. wroughtoni and the latter was found attacking coconuts. 11. Vandeleuria oleracea Found inhabiting trees and under grass growth around crop fields. 12. Golunda elliotti Found in forest and in thick grass growth around crop fields. 13. Millardia meltada meltada Seen in paddy fields in Wyanad, Calicut district. 14. Rattus raniiniae A new species of rat found in Trivandrum District. 15. Platacanthomys lasiurus A spiny rat damaging cashewnut in Idukki district. Study on indigenous rat traps. A total number of 17 indigenous rat traps were collected from various parts of Kerala. Among the various traps, Moncompu traps, for capturing rice field rats, bamboo-noose trap for trapping mole rat from live burrows, and the bamboo bow-trap for capturing rats infesting coconut crowns were found most useful.ThesisItem Open Access Factors affecting yield in cashew (Anacardium occidentale L.)(Department of Horticulture (Pomology & Floriculture and Landscaping), College of Horticulture, Vellanikkara, 1979) Parameswaran, N K; KAU; Damodaran, V KInvestigations on the different vegetative, flowering and fruiting characters, influencing yield in cashew, were undertaken at the main campus of Kerala Agricultural University at Vellanikkara. These studies were made during the period from November 1978 to April 1979. Important vegetative characters studied were the percentage of flowered shoots per unit area of tree canopy and the growth parameters of the tree represented by spread and height. The major flowering and fruiting characters studied were the pattern of flower opening, percentage of bisexual flowers, factors affecting pollination, fruit-set, fruit-drop and the mean weight of nuts harvested. The results showed that among the vegetative characters, percentage of flowered shoots per unit area of tree canopy was found to be the most important factor, contributing to yield. Tree-spread was also found to have a positive correlation with yield. The influences of this character on yield was not direct but indirectly through the former character. There was no significant correlation between yield and height of the tree. Pattern of flower opening in cashew panicles was found to have three phases viz., the first male phase followed by a mixed phase which is again followed by a second male phase. The duration of these three phases was found to be varying in the different trees. It was found that some trees had only the mixed phase throughout and those trees yielding above the median had a longer mixed phase as compared to the trees yielding below the median. A positive correlation was found between yield and percentage of bisexual flowers in the tree. Among the flowering and fruiting characters affecting yield, this factor was found to influence yield much more than any other character. Examination of a random number of bisexual flowers revealed that a large proportion of bisexual flowers remained unpollinated in nature. So, lack of pollination was found to be one of the reasons for poor fruit-set and yield in cashew. This was further confirmed from the high fruit-set obtained in the hand pollinated panicles. Receptivity of the stigma was found to be continuing up for 48 hours after flower opening and hence it was not a limiting factor for securing high yield. Supplementing the natural pollination with the help of insect pollinators met with some success. Keeping bee-hives in the orchards during flowering season is advisable for facilitating better pollination. A positive correlation could be observed between yield and percentage of fruit-set but the ultimate yield was found to be adversely affected by the severe shedding of young fruits before reaching maturity. The intensity of fruit-drop was found to be high in the early stages of development but it declined during the later stages. The causes of fruit-drop that could be identified were those resulting from the attack of insect pests, adverse climatic conditions etc. Studies did not reveal any significant correlation between yield and mean weight of nuts harvested.
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