Browsing by Author "Voleti, S.R."
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Item Biochemical changes and leaf water status of coconut genotypes differing in drought tolerance(2007-02-08) Shivashankar, S.; Nagaraja, K.V.; Voleti, S.R.; Kasturi Bai, K.V.Item Comparative physiological studies on the drought tolerance of three hybrids of coconut(2007-02-08) Shivashankar, S.; George, K.M.; Rajagopal, V.; Voleti, S.R.Drought tolerance of three hybrid crosses developed at CPCRI, Kasaragod were compared using physiological and morphological indices. Leaf water potential, stomatal resistance and specific leaf weight measured during stress and pre-stress periods indicated that MYD x WCT possessed better ability to conserve moisture. Morphological parameters also gave similar results. Based on the data, the three hybrids could be ranked for drought tolerance in the order, MYD x WCT > MOD x WCT > COD x WCTItem Comparison of physiological and biochemical parameters of coconut hybrid seedlings(2007-02-08) Voleti, S.R.; Shivashankar, S.; Rajagopal, V.Annual rate of leaf production, leaf area, leaf dry weight, increase in height and girth of four year old seedlings of MYD x WCT were higher than those of COD x WCT and MOD x WCT. Activities of enzymes such as nitrate reductase and malate dehydrogenase was higher in MYD x WCT whereas that of acid phosphatase and glutamic-oxalic acid transaminase more in COD x WCT. Thus under irrigated conditions, the superiority of MYD x WCT hybrid from nursery stage is being maintained over the other two hybrids.Item Growth and drymatter production in the component crops under monocropping and high density multispecies cropping systems(2007-02) Kasturi Bai, K.V.; Voleti, S.R.; Ramadasan, A.; Kailasam, C.Growth and dry matter production of the crops grown under monocropping and coconut bated high density multispecies cropping systems (HDMSCS) have been compared. Canopy growth aid economic yield of intercrops under HDMSCS were considerably affected. The energy output/input based on NPK as active ingredients also was lower for the intercrops under HDMSCS system. Lower light intensity reaching the canopy of intercrops due to interception by coconut canopy appears to be the limiting factor for their growth and productivity. Shade loving species which require low light intensities are likely to perform better under HDMSCS system. Identification of such species of economic Importance for trying in HDMSCS system is desirable.Item Impact of atmospheric and soil drought on the leaf water potential and membrane stability in coconut genotypes(2007-02) Kurup, V.V.G.K.; Voleti, S.R.; Rajagopal, V.The seasonal variations in stress parameters like leaf water potential and electrolyte leakage were studied in the popular coconut cultivar namely West Coast Tall (WCT) and the two hybrids WCT x Chowghat Orange Dwarf (COD) and COD X WCT, in relation to weather variables and soil moisture content. There was a significant difference in physiological parameters among the genotypes only during the stress period, characterized by high evaporative demand. The hybrid COD x WCT was found to be most sensitive to moisture stress as indicated by low leaf water potential, and high electrolyte leakage. This implies that the tall genotype and the hybrid with tall female parent (WCT X COD) are relatively more tolerant to moisture stress than the hybrid with dwarf female parent (COD X WCT).Item Influence of soil type on the development of moisture stress in coconut(Cocos nucifera L.)(2007-02) Voleti, S.R.; Nambiar, C.K.B.; Rajagopal, V.; Kasturi Bai, K.V.The response of three coconut genotypes namely West Coast Tall (WCT), WCT x Chowghat Orange Dwarf (COD) and COD x WCT to moisture stress on red sandyloam and laterite soils was studied. High evaporative demand in the atmosphere combined with high soil nter deficit during March 1988 (stress period) affected coconut palms to different degrees on the two soil types. The palms suffered more on ltd sandy loam soil than on laterite soil, as shown by the stomatal regulation and leaf water potential components/Both the hybrids could wi-Astand drought better on laterite than on sandyloam soil. A preliminary understanding of the genotype-environment interaction in coconut m thus achieved.Item Influence of Weather Variables on the Content and Composition of Leaf Surface Wax in Coconut(2007-02) Kurup, V.V.G.K.; Voleti, S.R.; Rajagopal, V.The epicuticular wax content (ECW) was estimated in rainfed coconut genotypes namely, West Coast Tall (WCT), WCT x Chowghat Orange Dwarf (COD) and COD x WCT between October, 1987 and August, 1988, with simultaneous measurement of weather parameters like light, temperature and relative humidity. The weather data revealed the prevalence of atmospheric and soil drought between January and May, 1988. The ECW content was higher during drought than during the non-stress periods. Thin layer chromatographic separation of the wax components indicated their qualitative differences at different seasons and among coconut genotypes.Item Leaf Characteristics And Dry Matter Production In Coconut (WCT And CDO X T) Grown Under Conditions Of Low And High Drought Intensities(1986-05) Rajagopal, V.; Kasturi Bai, K.V.; Ramadasan, A.; Balasimha, D.; Voleti, S.R.; Patil, K.D.; Sumathy Kutty Amma, B.; Varkey, T.; Mathew, A.S.; Gopalakrishnan Nair, M.Item Leaf Water Potential as an Index of Drought Tolerance in Coconut (Cocos nucifera L.)(1988) Rajagopal, V.; Shivashankar, S.; Kasturi Bai, K.V.; Voleti, S.R.Leaf water potential as an index of drought tolerance in coconut (Cocos nucifera L.). Rajagopal V, Shivishankar S, Kasturibai K V, and Voleti S R. (PI. Physiol. & Biochem. Divn., Central Plantation Crops Res. Inst., Kasaragod 670 124, India). PI Physiol. & Biochem. 15(1) : 80-86, 1988—Coconut genotypes were screened for drought tolerance using the leaf water potential (Item Physiological and Biochemical Criteria for Breeding for Drought Tolerance in Coconut(2007-02) Rajagopal, V.; Voleti, S.R.; Kasturi Bai, K.V.; Shivashankar, S.The ability of coconut genotypes to withstand drought conditions depends upon various physiological and biochemical factors which impart drought tolerance. Among these, the pattern of soil moisture depletion by the roots and transpirational loss of water through the leaf surface were found to be important. The accumulation of wax on the leaf surface and the stability of the activity of certain enzymes were found to have a bearing on stress tolerance. On the basis of the above criteria, .coconut genotypes were ranked according to the degree of tolerance. The hybrids, WCT x WCT, LO x GB, LO x COD and WCT x COD ; the tails, WCT ( selections) and Andaman Giant proved to be drought tolerant having a relatively high depletion of soil moisture by the roots, low transpirational loss from the leaf surface and the high content of cuticular wax, all desirable traits in the conservation of water by the tissues. The dwarfs, COD, MYD, GB and MOD; the tall cultivar, Laccadive Micro; and the hybrid, COD x WCT were characterized by an imbalance of water relations. Their low soil moisture depletion and higher rate of transpiration resulted in their susceptibility to drought; these genotypes also had low wax deposition. Further evidence was obtained through the determination of enzyme activities of glutamate oxalacetic transaminase (GOT) and acid phosphatase (APH), which showed distinct differences between the tolerant and susceptible genotypes. Thus, the much needed link between cellular processes and external manifestation of stress symptoms in coconut was established. The implications of these findings in the breeding programme for drought tolerance in coconut are discussed.Item Relative Water Content and Proline Accumulation in Coconut Genotypes Under Moisture Stress(1990-12) Voleti, S.R.; Kasturi Bai, K.V.; Rajagopal, V.; Shivashankar, S.Response of two tails (West Coast Tall, WCT, and Laccadive Ordinary, LO) two dwarfs (Chowghat Orange Dwarf, COD and Gangabondam, GB) and four hybrids viz., WCT x COD, COD x WCT, LO x GB and LO x COD of coconut to moisture stress simulated with an osmoticum of 30% polyethylene glycol (PEG - 6000 mol. wt) and air desiccation for similar period of 24 h was investigated. The two methods of simulation had differential effect on the genotypes. In general the relative water content (RWC) of leaves of all the genotypes was reduced more due to air desiccation than the osmotic stress. However the accumulation of proline did not differ much between the two types of stress simulation, except in the dwarfs which exhibited higher proline content in PEG - stressed leaves than in air desiccated ones. There was inverse relationship between RWC and proline accumulation. The data revealed that proline content is not associated with drought tolerance in coconut.Item Relative Water Content And Proline Accumulation In Coconut Genotypes Under Moisture Stress(1990) Voleti, S.R.; Kasturi Bai, K.V.; Rajagopal, V.; Shivashankar, S.Response of two tails (West Coast Tall, WCT, and Laccadive Ordinary, LO) two dwarfs (Chowghat Orange Dwarf, COD and Gangabondam, GB) and four hybrids viz., WCT x COD, COD x WCT, LO x GB and LO x COD of coconut to moisture stress simulated with an osmoticum of 30% polyethylene glycol (PEG - 6000 mol. wt) and air desiccation for similar period of 24 h was investigated. The two methods of simulation had differential effect on the genotypes. In general the relative water content (RWC) of leaves of all the genotypes was reduced more due to air desiccation than the osmotic stress. However the accumulation of proline did not differ much between the two types of stress simulation, except in the dwarfs which exhibited higher proline content in PEG - stressed leaves than in air desiccated ones. There was inverse relationship between RWC and proline accumulation. The data revealed that proline content is not associated with drought tolerance in coconut.Item Screening of coconut genotypes for drought tolerance(1990) Rajagopal, V.; Kasturi Bai, K.V.; Voleti, S.R.Twenty-three genotypes of coconut (Cocos nucifera L.) comprising ten tails, six dwarfs and seven hybrids were screened for their tolerance to drought using the sensitive parameters viz. stomatal resistance (rs), leaf water potential (i//) and epicuticular wax content (ECW). Coconut palms had varying responses to the prevailing soil and atmospheric droughts during the summer months. In general, tall genotypes had relatively high rs, \\\\j/ and ECW content as compared to the dwarfs. Some of the hybrids resembled the female parent in these characters. In response to the development of water stress between November and March some of the tall palms and tall hybrids showed relatively high rs resulting in effective conservation of water in the tissues (i.e. low transpiration rate), whereas the dwarfs were sensitive to stress with a tendency to lose more water. Parametric relationships with drought tolerance based on the rank sum led to the identification of few genotypes tolerant to drought with the desirables characters.Item Screening of coconut genotypes for drought tolerance(1990) Rajagopal, V.; Kasturi Bai, K.V.; Voleti, S.R.Twenty-three genotypes of coconut (Cocos nucifera L.) comprising ten tails, six dwarfs and seven hybrids were screened for their tolerance to drought using the sensitive parameters viz. stomatal resistance (rs), leaf water potential (¥) and epicuticular wax content (ECW). Coconut palms had varying responses to the prevailing soil and atmospheric droughts during the summer months. In general, tall genotypes had relatively high rs, ¥ and ECW content as compared to the dwarfs. Some of the hybrids resembled the female parent in these characters. In response to the development of water stress between November and March some of the tall palms and tall hybrids showed relatively high rs resulting in effective conservation of water in the tissues (i.e. low transpiration rate), whereas the dwarfs were sensitive to stress with a tendency to lose more water. Parametric relationships with drought tolerance based on the rank sum led to the identification of few genotypes tolerant to drought with the desirables characters.Item Water Potential In The Leaves Of Coconut (Cocos Nucifera L.) Under Rainfed And Irrigated Conditions(1993) Voleti, S.R.; Kasturi Bai, K.V.; Rajagopal, V.Item Water Relations Of Coconut Palms As Influenced By Environmental Variables(1988) Kasturi Bai, K.V.; Rajagopal, V.; Voleti, S.R.The influence of the agrometeorological parameters of radiation, temperature and vapour pressure deficit (VPD) on the development of stress in coconut palms (Cocos nucifera l. ) was studied. A steady state porometer was employed to measure both meteorological parameters and stomatal resistance under field conditions. Between 10.00 and 12.00 hours there were increases in radiation, temperature and vapour pressure deficit (VPD). During this period the stomatal resistance reached a maximum and the leaf water potential (¥) was reduced. During the wet season there was low radiation, temperature and VPD which resulted in the palms showing low stomatal resistance, whereas during the dry season the reverse situation occurred. West Coast Tall palms responded to dry weather through a high leaf diffusive resistance, while the hybrid dwarf X tall was susceptible to stress conditions.Item Water Relations of Coconut Palms as Influenced by Environmental Variables(1988) Kasturi Bai, K.V.; Rajagopal, V.; Voleti, S.R.The influence of the agrometeorological parameters of radiation, temperature and vapour pressure deficit (VPD) on the development of stress in coconut palms (Cocos nucifera l. ) was studied. A steady state porometer was employed to measure both meteorological parameters and stomatal resistance under field conditions. Between 10.00 and 12.00 hours there were increases in radiation, temperature and vapour pressure deficit (VPD). During this period the stomatal resistance reached a maximum and the leaf water potential (¥) was reduced. During the wet season there was low radiation, temperature and VPD which resulted in the palms showing low stomatal resistance, whereas during the dry season the reverse situation occurred. West Coast Tall palms responded to dry weather through a high leaf diffusive resistance, while the hybrid dwarf X tall was susceptible to stress conditions.Item Water Stress in Coconut (Cocos nucifera L.) Palms(1988) Rajagopal, V.; Kasturi Bai, K.V.; Voleti, S.R.; Shivashankar, S.Effect of soil moisture on morphological, physiological and biochemical responses of coconut genotypes was studied. The genotypes responded to moisture stress to different degrees. The number of drooping leaves was higher in COD x WCT than WCT and WCT x COD. WCT and WCT x COD had higher stomatal resistance, and leaf water potential than COD x WCT. Under stress, there was an increase in epicuticular wax in all the genotypes. The enzymes, add phosphatase and glutamate - oxaloacetate transaminase, were enhanced during stress conditions. The yield characteristics between rainfed and irrigated palms revealed that there was greater decrease in total nut yield and kernel dry weight in COD x WCT than that in the other two genotypes.