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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 Response of tomato to varying levels of fertigation(Department of Agronomy, College of Horticulture, Vellanikkara, 2002) Rajaseelan Kingsly, D; KAU; Jaikumaran, UA field experiment was conducted during 2000-2001 at the Agricultural Research Station, Mannuthy, Thrissur to find out growth and yield as well as water use and nutrient relations of tomato, as influenced by different levels of fertigation i.e. continuous nutrition through drip irrigation. The experiment consisted of combinations of three levels of irrigation (0.3,0.6 and 0.9 PE) through drip system and three levels of fertilizer (100, 50 and 150% recommended dose) supplied through drip irrigation. The fertilizer nutrients were supplied in progressive increments for sixty days and the fertigated treatments were mulched using black HDPE sheet. A control treatment, which received 20 mm surface irrigation through furrow method once in three days along with normal soil application of fertilizer without mulch cover was also included to compare with fertigation treatments. The experiment was laid out at randomised block design with three replications. The tomato CV Shakthi was tried in the experiment. The results revealed that the growth parameters viz., plant height, Leaf Area Index (LAI) and ~eaf Area Duration (LAD) were higher in the fertigated treatments than in the control crop. The respective values were 50.48 cm, 5.60 and 113.4 in case offertigated crops and 48.52 cm, 5.46 and 110.9 for the control crop, when observed at final growth stage. The control crop had a significant rooting pattern with higher vertical length (26.8 cm), lateral length (15 cm) and root dry weight of (8.2 g) than the fertigated treatments which had the respective values of 18.65 cm, 11.00 cm and 3.9 g. The ferigated crop produced maximum fruit set of 56.5 per cent and 36 numbers of fruits plant" with mean yield of 31.51 t ha-I. The respective values for the control crop were 42.6 per cent, 22 and 19.31 t ha" only. The treatment which received 150 per cent fertilizer dose with 0.6 PE irrigation gave a maximum yield of37.3 t ha-I which was 93 per cent more than the control crop. This level of production was comparable with that of the crop receiving 100 or 150 per cent recommended dose of fertilizers with irrigation at 0.9 PE through drip. The TSS content was not influenced by different treatments, but higher acidic fruits were produced by the control crop. The fertigated crops in general contained more nutrients in their biomass compared to control crop. The highest NPK content in plant was recorded at 60 DAP and at the stage these nutrient contents were 4.9,0.285 and 3.13 per cent in case offertigated crops and the respective values in control crop were 4.0, 0.245 and 3.07 per cent. The fruit cracking and bacterial wilt incidence were not affected by various treatments. But 72 per cent of control crop suffered by leaf curl virus disease but only 40 per cent, in case of fertigated plants. The mean soil temperature upto 30 cm depth increased "<-;- under mulched conditions over control treatment during morning (7.;3<) 1ST) and 'L.C;;- evening (2.:Mt 1ST) by 3.3°C and 2.6°C respectively. While control crop received 700 mm of water, the crop irrigated through the drip at 0.9, 0.6, 0.3 PE received 506, 358 and 210 mm of water. Field water use efficiency was the highest in the treatment which received 100% fertilizer with 0.3 PE irrigation (14.62 kg fruit per m-3 of water). As the irrigation levels reduced and fertilizer application increased FWUE was increased. The moisture content of the soil was more at 15 cm depth both at 15 and 30 cm radial distances, in all irrigation levels. The economic analysis indicated that the crop under recommended dose of fertilizer with 0.9 PE irrigation gave a maximum BC ratio of 1.92 followed by the crop raised under 150 per cent fertilizer dose with 0.6 PE irrigation (1.91). The saving of water through respective treatments, when compared to control enabled 0.38 and 0.95 ha to be additionally brought under irrigated tomato, if respective treatments were employed. The investigation led to the conclusion that fertigation is a sound technology and produceshigh yields in tomato. If water is not a limiting factor, adopt irrigation at 0.9 PE using 100 per cent recommended dose of fertilizer and if water availability is - constrained, adopt irrigation at 0.6 PE using 150 per cent recommended dose of fertilizer to reap rich harvest.ThesisItem Open Access Nutrient management for basmati rice (oryza sativa L) in wetlands(Department of Agronomy, College of Agriculture, Vellayani, 2002) Sindu, M S; KAU; Annamma, GeorgeA field experiment was conducted at the Instructional Farm, College of Agriculture, Vellayani from September 2001 to January 2002 to derive an optimum package for nutrient management for basmati rice in wetland condition. The experiment was laid out in factorial RBD with three replications. The treatments consisted of three levels of N (60, 90 and 120 kg N ha"), two sources of N (SI: SO per cent N as FYM and SO per cent N as chemical fertilizer and S2 : SO per cent N as vermicompost and SO per cent N as chemical fertilizer), two NPK ratios (2 : 1 : 1 and 2 : 1 : I.S) and an absolute control thereby forming 13 treatment combinations. Results of the experiment revealed that the effect of both N levels and NPK ratios had significant influence on most of the biometric and yield attributing characters and yield of basmati rice. Nitrogen @ 120 kg ha-I and NPK ratio of 2 : 1 : I.S were found significantly superior to lower levels. Eventhough the effect of sources of N was significant on plant height and dry matter production, the effect was not visible on the yield attributing characters and yield of the crop. A significant linear increase in grain yield was recorded upto 90 kg N ha-I , and thereafter the increase in grain yield was marginal. But the straw yield increased linearly with increase in N level and was also significantly influenced by the sources of nitrogen. NPK ratio of 2 : 1 : I.S recorded higher grain and straw yield. Nitrogen @ 120 kg ha-I and NPK ratio of 2 : I : I.S produced the highest grain protein content. The cooking time of grains increased with increase in N level. Nitrogen @ 120 kg ha-I and NPK ratio of 2 : I : I.S recorded the highest uptake of nutrients. Use of vermicompost for substituting 50 per 1'9 cent N resulted in the highest uptake of Nand P while the effect on K uptake was not significant. An increase in N application resulted in an increase in available N and P status of the soil after the experiment. Nitrogen @ 120 kg ha ", use of vermicompost for substituting 50 per cent Nand NPK ratio of 2 : 1 : 1.5 registered significantly superior available K status in the soil. The maximum NUE in terms of agronomic efficiency and apparent recovery was observed at 90 kg N ha-! and thereafter it decreased with the increase in N level. Application ofNPK in 2 :. 1 : 1.5 ratio also resulted in higher NUE. Sources of N were significant only with respect to apparent recovery and substituting 50 per cent N with vermicompost registered superior value. The physical optimum dose of N for grain yield and agronomic efficiency were worked out to be 109.24 and 94.67 kg N ha-! respectively. Straw yield exhibited a linear response to applied nitrogen. An increase in N level increased the disease incidence while a significant reduction in disease incidence was observed with the NPK ratio of 2 : 1 : 1.5 over 2 : 1 : 1. The highest net returns and BCR were recorded when FYM was used to substitute 50 per cent of nitrogen. Increase in N levels upto 90 kg ha-! and application of NPK in' 2 : 1 : 1.5 ratio was found profitable. So a fertilizer dose of 90 : 45 : 67.5 kg NPK ha-! with 50 per cent N as FYM and 50 per cent N as chemical fertilizer can be recommended for maximizing the yield and returns of basmati rice in wetlands.ThesisItem Open Access Effect of nutrient inter-relations on productivity of rice in lateritic soils(Department of Agronomy, College of Horticulture, Vellanikkara, 2002) Sindhu, P V; KAU; Meera Menon, VThe effect of nutrient inter-relations on productivity of rice in latritic soils was investigated during the first crop season (Virippu) Or 1999-2000 at the Agricultural Research station, Mannuthy. The objective of the study was to arrive at the minimum level combination of applied elements for maximum productivity based on the interaction pattern between applied and native elements so as to develop a sustainable management system. Jyothi was used as the Fest variety to analyse the pattern of interacting influences of P, K, Ca and S at two levels each, among themselves as well as on the native elements. The results showed that treatments had significant beneficial influence on yield expression, causing 90 and 10% increases in yield over absolute control and the presently recommended package of practices. This indicated the necessity of including Ca and S in the nutrient management system. Decline in chlorophyll content and high levels of cell sap pH, together with excess contents of Fe and Zn appear to act as the supressors of yield expression. The latter influences are inherent in soil and are actually the net product of the balance between positive and negative effects of nutrients. A significant finding was that application of any element by itself was not a guarantee for its uptake, and was subject to the effect of other elements, and similarly, had direct or indirect influences on other elements. The positive influence of K and Ca at the maximum tillering and S at the panicle initiation stage, and negative influence of Fe and Mn at the panicle initiation stage pointed out to the need for phasic management of nutrients. The only element inhibiting Fe uptake had been Si, suggesting that the reversal of the process of laterisation holds the key to higher yields. Discriminatory transfer of individual elements between leaf blade and leaf sheath appeared to be an important regulatory factor in deciding yield expression. Highest yield resulted when blade-sheath ratio was maximum tillering and panicle initiation declined in respect of Ca, Fe and Mn and increased in respect of K and S. the study resulted in development of the broad base of a management technology for high productivity and sustainability. The components included keeping N at the present reconunended level, reducing P by 50%, increasing K by 100% and top dressing N using s containing fertilizers as well as moderate basal dressing with Ca.ThesisItem Open Access Response of chilly to plant growth promoting rhizobacteria fluorescent pseudomonads(Department of Agronomy, College of Agriculture, Vellayani, 2003) Anu, V; KAU; Elizabeth Syriac, KThe research project entitled 'Response of chilli (Capsicum annuum L.) to plant growth promoting rhizobacteria fluorescent pseudomonads' was carried out as two investigations viz., a pot culture trial and a field study at the College of Agriculture, Vellayani, during July 2002 to April 2003. The study was conducted on chilli cultivar, Jwalasakhi. The pot culture study was aimed at evaluation of fluorescent pseudomonads isolates for growth promotion and yield in chilli. The treatments consisted of five different isolates of fluorescent pseudomonads (PI, P5, P14, P22and KKI6). The trial was laid out in completely randomised design with four replications. Among the five isolates tested, isolate P22 was adjudged as the best one for growth promotion and P I for disease resistance. As far as yield and economics are concerned, these two isolates were found to be on par. Thus a dual culture of Tsolate P22 and PI was selected for further field study. The objective of the field study was to assess the suitability of the best isolate of fluorescent pseudomonads as a biofertilizer either alone or in combination with Azospirillum along with different doses of NPK . fertilizers on growth and productivity of chilli. The field study was laid out in factorial randomised block design with three replications. The different treatments included three different levels of NPK (75 per cent (56.3 : 30 : 18.8 kg ha"), 100 per cent (75 : 40 : 25 kg ha') and 125 per cent (93.8 : 50 : 23.5 kg ha-I) of the recommended dose of NPK as per POP) and four biofertilizer treatments (Fluorescent pseudomonads, Azospirillum; Fluorescent pseudomonads + Azospirillum and no biofertilizers). The abstract of the result is furnished below. r I~ All the growth characters increased significantly with graded doses or PK. Combined inoculation of fluorescent pseudomonads and Azospirillum was the most superior one among biofertilizer treatments. Similar trend was also observed for yield attributing characters. However with regard to marketable fruit yield, all the levels of NPK fertilizers tested were statistically on par. With respect to biofertilizer application, combined inoculation (7.75 ha") was on par with fluorescent pseudomonads application (7.56 t ha-I). Compared to control of no biofertilizer treatment, Fluorescent pseudo monads + Azospiriflum increased fruit yield by 46.69 per cent. Among the treatment combinations, 75 per cent of the recommended dose of NPK (56.3 : 30 : 18.8 kg ha-I) + Fluorescent pseudomonads + Azospirillum produced significantly higher yield (8.74 t ha-I) and ensured a saving of 25 per cent of recommended dose of NPK. 100 per cent POP + Fluorescent pseudomonads application was on par with this treatment. At 125 per cent of the recommended dose of NPK (93.8 : 50 : 23.5 kg ha I) microbial count in the rhizosphere was significantly lower and fruit rot incidence was significantly higher. Biofertilizer application significantly increased microbial count and reduced disease incidence. 75 per cent of recommended dose of PK + Fluorescent pseudomonads + Azospirillum was rated as the most economically viable treatment combination, with a net profit and benefit-cost ratio of Rs. 59328 ha-I and 1.82 respectively.ThesisItem Open Access Integration of nutritional inputs for improving rice productivity in laterite soils(Department of Agronomy, College of Horticulture, Vellanikkara, 2003) Jinappa, Halingali; KAU; Usha, K EA study on "Integration of nutritional inputs for improving nee productivity in laterite soils" was taken up during 2001-2003 at the College of Horticulture, Vellanikkara The experiment consisted of 17 treatments including two sources of organic manure and two levels of nutrition with combinations of lime and silica to develop a cost effective, high yield and sustainable production technology for rice by identifying the components of good management. The treatment .receiving poultry manure with 90 kg ha" of fertilizer N and 500 kg ha" of silica recorded the maximum height productive tillers, •number of spikelets per panicle and thousand grain weight which . contributed to the maximum grain yield 0[7004 kg ha". An increase in 1680 kg grain yield and 1087 kg straw yield than the package of practices recommendation of Kerala Agricultural University appear to be due to the application of Silica, substitution of cow dung by the poultry manure and increased dose of N with an organic: inorganic ratio of 1 :2.25, increased dose ofK and reduced dose ofP. Cow dung contains Fe, Zn and Cu in toxic levels to rice. Poultry manure has the content of these elements in far less quantities but has higher Ca content . which helps in reducing the uptake of unfavourable elements by the rice plants. Increase in'the level of K application @120 kg ha' has recorded 1387 kg ha" more grain than the present recommendation of 35 kg ha" and the uptake of K by the plants are far above the applied levels. This suggests that the present recommendation of35 kg ha' ofK has to be enhanced up to 120 kg ha" to prevent the soil degradation. It is also seen that the rice plants absorb only around 20 kg P and hence the P recommendation can be reduced from 35 kg to 20 kg ha". There was no apparent effect when lime and silica were applied together but individually they could improve the yield. The number of weeds and the incidence of pests and disease were less in thetreatment plots, which revealed the influence of soil ameliorants in impa~ing resistance in the rice pants. TIle. results of the present study indicate that the failure of rice plants to respond to higher doses of fertilizer N, appears to be because of the unfavourable organic: inorganic' ratio. A ratio of 1 :2.25 was found to be beneficial to nullity the unfavourable chemical effects of fertilizer N.ThesisItem Open Access Standardisation of mat nursery for rice(Department of Agronomy, College of Horticulture, Vellanikkara, 2003) Rajesh, G; KAU; Jaikumaran, UA field experiment was conducted during May to September 2002 at the Agricultural Research Station, Mannuthy, Thrissur to develop a suitable production package for rice mat nursery, evaluate it under mechanical transplanting and develop it as a substitute for conventional nursery for manual planting. The s~dy consisted of three experiments. (J) Raising of sixteen types of mat nurseries using . . four different media in two ratios under two systems (dry and wet) and its evaluation. (II) Mechanical transplanting of these sixteen types of mat nurseries along with manual planting of conventional nursery and crop performance study. (Ill) Manual transplanting of sixteen types of mat nursery along with conventional nursery and crop evaluation. Experiment-I was designed in GRD, while experiment-II and experiment-Ill were laid out in Randomised Block Design, with two replications each. Rice variety Kanchana, was tried in the experiment. Results revealed that soil+ cow dung in the ratio 2: 1 in the mat produced taller seedlings and coir pith compost produced shorter seedlings. Presence 'of cow dung produced dark green seedlings with maximum number of healthy and minimum number of weak seedlings. Soil+ cow dung in the ratio 2:1 produced heavy mats under both systems. Presence of chaff in the media resulted in stronger mats. The performance of the transplanter, as it is a fixed parameter for the machine was unaltered by the different media and systems of nursery. But generally, the , '. number of missing hills was lower under dry system, compared to wet system. In case of experiment-Il, a higher plant population of 65 hills m-2 was seen associated with the crop raised under manual planting using conventional nursery. But the same crop produced a significantly lower number of tillers hill-1 throughout its growth period and the crop had 9.5 tillers nnr', at the time of harvest. The physiological growth attributes, observed through CGR, RGR and NAR was distinctively lower for the manuaIIy planted crop using conventional nursery in the initial stages of growth, but the trend disappeared in the later stages, indicating a uniform rate of growth. The insect pest attack was uniform without any variation due to treatments. Incidence of BLB was higher in case of mechanically planted crop using soil+ coir pith compost in 2: 1 ratio under dry nursery and soil+ coir pith raw in 2:] ratio under wet nursery. Among the yield components, number of 'panicles m-2 and test weight were not altered by the treatments. The maximum number of filled ,grains panicle" was seen in case of soil+ cow dung in the ratio 2:] ,as the media under dry system (61). However, the final grain and straw yield remained unaffected due to the various treatments with a mean value of 4344 and 7464 kg ha" respectively. The NPK content of the grain and total uptake ofP and K by the crop were influenced by the various treatments. Under dry system soil+ coir pith raw and soil+ chaff in the ratios 2: 1 and in wet system soi1+ cow dung in the ratio 1:2 and soil+ coir pith compost in the ratio 2: 1 were economically superior and can be the mat nursery media for mechanical transplanting. The use of mat nursery instead of conventional nursery did not prolong the time required for manual planting. Conventional nursery recorded a lower tiller production (8.8 at the time of harvest). Similar level of tiller production was seen in cases of soil+ chaff in either of the ratios and soil+ coir pith raw in the ratio 1:2. The pest and disease incidence, except rice bug, did not show any discrimination between the treatments. SoiI+ chaff in the ratio ]:2 under dry system had a higher population of bugs (2.7 per hill). Soil+ coir pith raw in the ratio 2: 1 under both the systems had the highest number of panicles m-2 i.e., 352 and 341, respectively. Conventional nursery had the lowest number of filled grains panicle" (31). The grain yield was unaffected, due to treatments and the mean grain yield was 4441 kg ha-I. Straw yield was influenced by the different treatments. A very low harvest index value of 0.3 was recorded for the crop. Crop raised using conventional nursery had a very low B:C ratio (l.05) and all mechanically planted crops had higher B:C ratio than this. As the grain yield was not affected due to the various treatments, the selection of mat should be based basically on economic consideration. Soil+ coir .pith raw as well as soil+ chaff in the ratio of 2: 1 under dry system, and soil+ cow dung in the ratio] :2 and soi1+ coir pith compost in the ratio 2:], under wet system could be a better option for mechanical transplanting based on the economics. Soil+ cow dung in 1:2 ratio and soi1+ chaff in 2: 1 ratio under both systems, and soil+ coir pith raw in 1:2 ratio under dry system and soil+ coir pith raw in 2: 1 ratio under wet system were found economically suitable. for manual planting.ThesisItem Open Access Weed management in semi- dry rice intercropped with green manure crops(Department of Agronomy, College of Horticulture, Vellanikkara, 2003) Resmy, O N; KAU; Jose MathewAn investigation was conducted during the kharif season of 2002 at Agricultural Research Station, Mannuthy to formulate weed management practices in semi-dry rice intercropped with green manure crops. Fourteen treatments were laid out in RBD with three replications involving combinations of two green manure crops (cowpea and horsegram) for in situ green manuring and six weed management treatments (butachlor, pendimethalin, pretilachlor, anilofos, handweeding and control) in addition to rice monocropping . . Results of the study revealed that an integrated strategy encompassing the application of pre-emergence herbicides and intercropping of green manure crops was successful from the point of view of weed management, organic manure addition and crop yield in semi-dry rice. Among the fourteen treatments tried, the highest yield of grain and straw was recorded by monocropped rice with hand weeding (T 13) which was on par with treatments intercropped with horsegram (Ts) and cowpea (T2), both receiving pendimethalin application. Intercropping with horsegram encouraged better growth of rice over cowpea. Averaging the grain yield of rice in intercropping treatments, it was found that concurrent growing of horse gram has significant superiority over cowpea. Comparing the unweeded plots with cowpea or horse gram intercropping and rice monocrop, it was observed that intercropping reduced the weed count to the extent of 42.8 to 56.8 per cent upto 60 DAS and cowpea was found superior in suppressing the population of weeds. The contribution of N, P and K by cowpea at the time of self decomposition was almost double that of horse gram, leading to an increased soil fertility status. Pendimethalin, pretilachlor and butachlor can be used safely both in rice + cowpea and rice + horsegram cropping systems and they favoured growth and yield of green manure crops and rice, apart from their superior weed control efficiency.ThesisItem Open Access Identification of drought tolerant cocoa types(Department of Agronomy, College of Horticulture, Vellanikkara, 2005) Binimol, B; KAU; George Thomas, CExperiments were conducted at the college of Horticulture, Vellanikkara to investigate the drought tolerant characteristics of the most promising cocoa varieties and accessions. The investigation involved a two-stage screening of cocoa seedlings and budlings and monitoring of their field grown plants. As the first step, a preliminary screening was done on six month old seedlings and budlings of ten cocoa cultivars released from Kerala Agricultural University and twenty promising accessions. A secondary screening of cocoa cultivars/accessions selected from the preliminary screening was then conducted. Simultaneously, field monitoring of cocoa trees of the varieties selected from the primary screening was also done. From the preliminary screening, seven apparently tolerant varieties were selected for secondary screening in both seedlings and budlings based on higher RWC and DWF, lower percentage of dried leaves and longer duration of life under during moisture stress. Three apparently sensitive verities were also selected based on opposite values of the above characters. Varieties identified in the preliminary screening were subjected to a secondary screening under three moisture regimes of no irrigation , watering once in five days (life saving irrigation), and regular watering. Observations on physiological parameters such as relative leaf water content, dry weight fraction, leaf drying percentage, number of days taken for complete drying, stomatal conductance, transpiration rate, leaf water potential, chlorophyll ‘a’, ‘b’ and total chlorophyll, chlorophyll stability index, leaf area per seedling, membrane stability, relative injury; growth characters like plant height, collar girth, number of leaves and total biomass; biochemical characters such as proline content and nitrate reductase activity were recorded. After conducting a cluster analysis, the varieties with high RWC, DWF, total chlorophyll content, leaf water potential and proline content; low stomatal conductance, transpiration rate and leaf area during water stress were rated as drought tolerant and with opposite characters as drought sensitive. Based on these, in seedlings; the varieties M 13.12, GII 19.5 and GVI 55 were ranked as moisture stress tolerant and GVI 61, GV 50 and GI 4.8 as sensitive under no irrigation. In budlings, the varieties GI 4.8 and GII 19.5 were selected as drought tolerant and GIII 4.1, GVI 51 and GII 12.3 as drought sensitive under no irrigation Important characters were also monitored in 16-year old clonal trees of the seedlings/budlings of the varieties selected from primary screening. Transpiration rate, stomatal conductance, leaf water potential, stomatal frequency, leaf thickness, bark thickness and soil moisture content were recorded during summer. The varieties GVI 61, M 13.12 and GI 4.8 showed drought tolerant features. The accession M13.12 (CCRP2) showed drought tolerant features in secondary screening of seedlings and field performance. The accession GVI 51, which showed sensitivity to moisture stress in seedlings (but tolerant in budlings) under secondary screening, was showing similar behavior of sensitivity in field grown plants. The study shows the possibility of exploiting drought tolerant features of cocoa varieties/accessions. However, final conclusions are difficult to be drawn as only 10 accessions were subjected to secondary screening and field monitoring, and data for only one year were collected. In the light of the promising results obtained, screening trails involving more number of varieties/accessions have to be conducted and monitored for more number of years to get consistent values.ThesisItem Open Access Integrated weed management in lowland rice(Department of Agronomy, College of Agriculture, Vellayani, 2004) Seema, V; KAU; Janardhanan Pillai, SA field experiment was conducted at Cropping Systems Research Centre (CSRC), Karamana, Thiruvananthapuram to evolve a suitable integrated weed management practice for lowland nee. The study was conducted during the viruppu season of 2003. The field experiment was laid out in randomised block design having three replication with twelve treatments. The treatments include different herbicides in combinations, herbicides + hand weeding, hand weeding twice and unweeded control. Butachlor, 2,4~D, pretilachlor, anilofos + 2,4-DEE, anilofos, ethoxysulfuron, metsulfuron methyl and chlorirnuron- ethyl were the different herbicides used in the experiment. The rice variety used for the experiment was Kanchana. The results of the study revealed that grasses, broadleaved weeds and sedges competed with the rice crop. Different weed management practices significantly influenced the intensity and distribution of weeds ... The lowest dry matter of weeds was recorded by anilofos + ethoxysulfuron followed by one hand weeding which was on par with anilofos -+ ethoxysulfuorn alone. All the weed management treatments resulted in improved yield attributes and higher grain yield compared to weedy check. The plots treated with anilofos + ethoxysulfuron followed by hand weeding at 40 DA T recorded the highest grain yield. This treatment resulted in enhanced plant height, number of productive tillers un', LAI and nutrient uptake of rice. The yield attributes and grain yield were significantly increased by this treatment. The total weed population, weed dry matter production and nutrient removal by weeds were also reduced and weed control efficiency was increased by this treatment. Unweeded control recorded the lowest gram yield. No herbicide used in this experiment resulted m residual toxicity after the cropping season. Manual weeding is expensive, laborious and time consummg. Labour non-availability at peak crop season for weeding also poses great threat. Readymix application of anilofos + 2,4-DEE (T3) resulted in highest B:C ratio of 1.41 and butachlor + 2,4-D (T,) with 1.40. Pre-emergence application of anilofos + ethoxysulfuron followed by one hand weeding at 40 DA T (T 8) was the most remunerative treatment.
