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Open Access
Incorporation of tomato leaf curl virus (Tolcv) resistance in bacterial wilt resistant tomato.
(Department of Olericulture, College of Horticulture, Vellanikkara, 2011) Koteswararao, Yadav; KAU; Sadhankumar, P G
Investigations on “Incorporation of Tomato Leaf Curl Virus (ToLCV) resistance in bacterial wilt resistant tomato” were undertaken in the Department of Olericulture, College of Horticulture, Vellanikkara during the period from January, 2009 to May, 2011. Eighty tomato genotypes collected from India and abroad were screened for ToLCV resistance of which 26 were found to be highly resistant under natural screening. Of these, 20 genotypes (LE-474, LE-635, LE-640, LE-658, LE-666, LE-667, Arka Ananya, IIHR-2195, IIHR-2196, IIHR-2197, IIHR-2198, IIHR-2202, IIHR-2747, TLBRH-1, TLBRH-6, Cherry Tomato, H-24, H-86, Hawaii-7998 and Rani) were highly resistant to ToLCV under both graft transmission and whitefly transmission there by confirming their resistance to ToLCV. Seventy six tomato genotypes were screened for bacterial wilt resistance in bacterial wilt sick plot. Spot planting with known suscept Pusa Ruby was done to confirm the presence of virulent bacteria in the field. Anagha, Sakthi, Mukthi, LE-1-2, LE-626 and LE-474 were resistant to bacterial wilt. Three additional sources of resistance were identified viz., LE-628, LE-640 and LE-649. Five bacterial wilt resistant genotypes (Anagha, Sakthi, Mukthi, LE-1-2 and LE-626) were crossed with seven ToLCV resistant genotypes (IIHR-2195, IIHR-2196, H-24, H-86, Hawaii-7998, LE-474 and LE-640) in a line x tester fashion. Thirty five F1 hybrids developed were screened for both ToLCV and bacterial wilt resistance. Thirty hybrids were highly resistant to tomato leaf curl virus (ToLCV) among the 35 hybrids. Sixteen F1 hybrids were resistant to bacterial wilt. There were 15 F1 hybrids which were resistant to both ToLCV and bacterial wilt. Line x tester analysis was performed to derive information on general combining ability and specific combining ability effects, gene action and heterosis. Good general combiners for different characters were identified. Among the F1 hybrids Anagha x LE-640 was the earliest to flower and earliest to harvest. Sakthi x LE-640 (1.4 kg/plant) gave the maximum yield among the hybrids and parents followed by Mukthi x H-86 (1.1 kg/plant) and LE-1-2 x Hawaii-7998 (1.06 kg/plant). Maximum number of fruits were produced by LE-1-2 x Hawaii-7998 (39.67 fruits/plant). The maximum sized fruits were produced by Anagha x IIHR-2195 (55.93 g) followed by Sakthi x LE-640 (55.78 g) and Sakthi x IIHR-2196 (55.09 g). F2 segregants of 35 crosses were screened for combined resistance to bacterial wilt and ToLCV. Thirty F2 segregants were resistant to both bacterial wilt and ToLCV. Mukthi x IIHR-2195-F2-47 (1.7 kg/plant) and Mukthi x IIHR-2195- F2-34 (1.5 kg/plant) were the highest yielders among the 30 segregants. Segregation pattern in F1, F2, B1 and B2 of the cross combination Pusa Ruby x IIHR-2195 revealed that the resistance to ToLCV in IIHR-2195 is controlled by a single dominant gene.
Open Access
Developmental physiology of banana corm (Musa AAB nendran) in relation to phenology, yield and quality
(College of Agriculture, Vellayani, 2011) Binu John, Sam; KAU; Sajan, Kurien
The study on “Developmental physiology of banana corm (Musa AAB Nendran) in relation to phenology, yield and quality” was taken up as a part of the fully funded DST project of the Ministry of Science and Technology, Government of India at the RARS, Kumarakom from 2004 to 2008. The study was basically centered on the corm and roots. The objectives of the study were to have a basic idea of the origin and development of the secondary corm as influenced by various factors, to identify and fix the stages of corm development and rooting in relation to biotic events (bud initiation, differentiation, shooting and suckering), to establish the root production pattern (continuous or cyclic), characterize the roots (pioneers or feeders), study the relationship of carbon assimilation and nutrient uptake on corm development, to have a basic understanding on origin and development of suckers, to study the genetic differences in corm and sucker development and finally to hasten out secondary corm formation thereby reducing crop duration without affecting post-harvest quality parameters. The major findings emanating from the studies are presented aspect-wise under different paragraphs. Planting was taken up at bimonthly intervals. Each planting consisted of fifty plants and observations on all characters were taken up. The height of the plant in the June planting was the highest followed by that in April, October and August. The December and February planting recorded the least height. April followed by February and August planting had the highest girth. December, followed by October and June recorded the lowest girth in the order. The number of leaves produced by the plant was in the range of 27-28 with very minor subtle difference between months of planting. The pattern of leaf production is very explicit, an increasing number of leaves are found to produce from upto FBD stage in case of June planting and in October planting this is found to increase upto shooting whereas in December and February, leaf production is very erratic and a small fall in production is observed in April. Number of new leaves emerging in a fortnight is found to increase in June and October planting upto FBI and is at the maximum. Whereas the December, February and April planting has revealed a very low number of leaf production and the maximum number of leaves produced is found to be in between SCI and FBI which could be one of the major reason for the low productivity. A critical analysis of the data reveals that an increasing number of leaves retained is observed upto FBD stage in case of October and April planting. In April planting this trend is observed only upto FBI stage whereas in December and February the maximum number of leaves retained is seen at the SCI stage. This reveals that number of leaves retained in the critical phases of FBI and FBD have a direct impact on the yield and yield components. The length of the ‘D’ leaf is found to increase upto the last phase in all the six crops. The maximum leaf length of leaf is observed in June planting. An increase in the breadth of leaf upto shooting is observed in October and December planting but thereafter the leaf width is found to decline from FBD to shooting. However in case of leaf area the June, October and December planting showed progressive increment in area. However maximum area in case of February and April were at FBD and FBI stage. The study confirms that June planting gave the highest yield and was over 10kg. This is due to water shortage in Early Vegetative, AVS and SCI and high water table as good as flooding at the stage of FBI due to heavy South West Monsoon experienced in the area. On the contrary, June planting received showers from planting and after shooting received adequate sunshine hours. The finger characters were more or less a reflection of the bunch weight. However the finger in August planting appeared straighter on maturity than June planting. One of the major findings emanating from the study is the efficiency factor heliothermal units/ photothermal units. The factor gives the concept of efficiency as it is a function of realized sunshine duration to the potential maximum at a location. The study confirms that when this factor is very near or exceeds 0.5 the yield tends to increase with inputs not being a limiting factor. The photothermal units (PTU) and heliothermal Units (HTU) requirement were almost a reflection of the same as that of GDD. A split up of the requirement from one biotic phase to the other again revealed an identical trend. The base temperature at which growth starts in banana was identified to be 140C. Secondary corm formation is an integral part of crop cycle of banana crop raised from suckers and it is being reported for the first time. The new corm was observed to develop above the planted corm. This planted corm gradually becomes necrotic, deteriorates and falls off towards the time the crop comes to maturity. All the six plantings in the calendar year prove this beyond doubt. The crop duration in sucker planted bananas are dependent on the secondary corm formation. Secondary corm formation is found to be a factor of corm size. This has been conclusively proved by the experiment using suckers of graded corm size. The time taken from SCI to FBI, FBD and Shooting and Maturity is almost same. Hence the change in crop duration of Nendran bananas can be explained on the basis of time taken to reach SCI. A definite GDD is required for the planted sucker to reach the SCI stage depending on corm size. The thermal unit requirement is based on the corm size and this explains the reasons for early bunch production of large sized corms The study has confirmed that the root production in banana is in flushes. Five flushes of roots are observed in a crop cycle. Overlapping of successive flushes of roots is observed giving a false appearance of continuous root production. Overall, the production of a flush of root takes place in about a fortnight’s time. Qualitative & quantitative differences are observed in the production of different flushes of roots. The study has confirmed that the flushing of roots is more dependant on the biotic events of the crop. The first flush of roots is observed in the early vegetative phase (EVS), about 3-4 weeks after planting ie. up to the production of four numbers of leaves. Thereafter, the root grows. The second flush of roots coincides with the active vegetative growth and from approximately the eighth or ninth leaf onwards. The third flush of roots is observed at the secondary corm initiation phase. The first and second flushes are observed purely on the primary planted corm whereas, the third is observed partly on the newly developing corm ie: the Secondary Corm and partly on the primary corm and on the constricted interphase part. The fourth flush of roots is observed at the flower bud initiation stage and the fifth flush at shooting or early bunching phase. These two flushes of roots carry the banana bunch to maturity. In the orderly cycle of development of banana, five distinct physiological phases such as Vegetative Phase, Flower Bud Initiation (FBI), Flower Bud Differentiation (FBD), Shooting and Bunch Maturity are normally described. In no literature has the corm ever been emphasized or even mentioned in the developmental physiology. The formation of the secondary corm was studied anatomically and the physiological factors governing the secondary corm formation was also studied by analyzing the mother corm tissues. The study has conclusively proven that a new corm develops on the planted corm and it is this new corm or the Secondary Corm which further carries the plant to bunching and harvest. Another observation is that the shooting or bunching is observed to be a factor of maturity of the new corm and the crop cycle or crop span or crop duration is found to be dependant on satisfaction of three main phases a) Primary corm to early secondary corm formation b) Secondary corm formation, maturation of secondary corm to bunching c) Bunch maturity and harvest During the second year, the experiments were focused on hastening of secondary corm development and early replacement of original corm of the sucker. For this, suckers of a medium corm size were fixed based on the first year’s experiment. In the study involving hormonal application, IAA, NAA, PCBA and ABA each at 250 and 500 ppm were advocated by corm dip method and corm injection method Hormone dipping treatment of suckers prior to planting and by corm injection after establishment revealed that early growth was suppressed by PCBA with drastic reduction in internodal length. Dwarfening of plant stature could be attained by using PCBA and ABA. This would pave the way for further research to mitigate the effects of wind or avoid staking which is a costly input. SCI was observed to be earliest in treatments involving IBA. However the control treatments were the earliest to bunch. The crop is yet to be harvested. The study has proven that maturity of secondary corm can be manipulated by exogenous application of growth regulators. The studies on root activity revealed spatial distribution of root activity and differential accumulation in various tissues which could be explained at tissue level and with time The importance of secondary corm and its accumulation in tune with the development physiology. On the fifth day after application recovery of activity was observed in the primary corm only at the FBD stage. On the 10th day after application (DAA) maximum recovery of activity was obtained in the primary corm at FBI stage. Sufficiently higher amounts were observed at Early Vegetative Stage (EVS), Active Vegetative Stage (AVS) and Half Maturity stage. On the contrary at 15th DAA the relative concentration was very much high in primary corm at EVS and AVS stage. The relative concentrations were six times that observed at SCI (third highest) in the former and double in the latter. As the crop advanced the concentration has decreased with single digit recovery at Half Maturity. In case of secondary corm (SC) on the fifth day, recovery of activity was only observed at FBD stage, whereas on the 10th day it was maximum observed at FBI stage. Highest recovery in SC is observed at shooting followed by Secondary Corm Initiation (SCI) stage, Half Maturity and FBI. At all stages a fairly good concentration is observed explaining for the growth of secondary corm. The relative levels in roots in the earliest and second sampling were observed at FBI stage whereas in the final sampling it was observed to peak at half maturity and shooting stage. The maximum recovery of radioactivity in the pseudostem were observed in the early two stages in the first sampling ie. FBI & SCI and AVS in the second and in early three stages in final sampling, revealing that nutrient absorbed is the maximum utilized for structural make up. In the final sampling, recovery was observed in the pseudostem in all the stages. In the case of recovery form the ‘D’ Leaf in early sampling, maximum recovery could be traced at FBI stage followed by that at half maturity and FBD. In this sampling recovery was not observed at any other stage. On the 10th DAA maximum recovery was observed at FBI followed by SCI, FBD and half maturity. No recovery was observed at any other stage. In case of the concentration in petiole of ‘D’ leaf maximum recovery was observed at FBI, Shooting, SCI and Half maturity on the second sampling. No radioactivity was recovered at any phase on the 5th DAA. However in the final sampling maximum recovery was observed at EVS, Shooting, SCI and Half Maturity. Recovery was observed at all stages in the 15th DAA. The boot leaf which subtends the bunch showed fairly good concentration at Half Maturity on the 15 DAA emphasizing the importance of the leaf with advance in fruit maturity. Lower levels were recovered at the shooting stage. On the 5th and 10th DAA no recovery were observed. In the case of ‘D’ finger the maximum recovery was observed at shooting stage on the first, second and third sampling. The levels being fairly high in the final sampling. In case of male bud increasing levels of recovery are observed with samplings. The levels being the highest in case of last sampling and being the highest sink per unit weight of tissue. At Half Maturity no recovery was observed at 5th and 10th DAA but in the final sampling again high level of recovery is observed. The study overwhelmingly emphasizes the need to debud the male inflorescence on the one hand and on the other major and important side it highlights this part as a vegetable with high P nutrient content. The first report on Carbon assimilation and transport in banana is also from the study. For this an innovative apparatus for the dissemination of 14C was fabricated after many a trial and error method. The apparatus is simple in design but accurate in its practicality and the first of its kind to be used in banana plants. The results from the studies involving 14C showed a holistic picture on the photosynthate translocation and assimilation to the various plant parts at different stages of its growth. During the initial stages (EVS & AVS), the accumulation was found to be the maximum at the source level itself. At SCI stage it was found to be more in the leaf petiole and pseudostem with no recovery in the primary corm. At the reproductive transformation stage of the plant (FBI & FBD), the entire assimilates were found to be translocated to the SC and Ps. At the shooting stage and the half maturity stage, the finger and male bud together account for the whole photosynthates whereby giving a marked reflection and manifestation of the functional requirement of the plant with the entire shifts focused at the sink level.
Open Access
Stimulation of growth and induction of variability in mangosteen (Garcinia mangostana L.)
(College of Horticulture, Vellanikkara, 2011) Manoj, P S; KAU; Sarah, T George
Mangosteen (Garcinia mangostana L.) is identified as a fruit crop deserving priority attention with a potential for increased acceptability. It is recognized as the ‘queen of tropical fruits’ due to its instant visual and taste appeal and has recently been popularized for its medicinal benefits. It yields profusely and fits very well as a component in the homesteads of Kerala. Almost all trees are female and variability is meagre. Its slow growth and long gestation period limit its commercialization. The present investigation on “Stimulation of growth and induction of variability in mangosteen (Garcinia mangostana L.)” was undertaken in the Department of Pomology and Floriculture, College of Horticulture, during 2006 - 2009 with the objective of developing techniques for accelerating seedling growth in the nursery, reducing gestation period and inducing variability through mutation and polyploidy. The studies on different growing media and growth regulators on seedling growth in the nursery revealed that potting mixture containing vermicompost as organic component was the most superior medium in terms of all the growth and physiological parameters, foliar nutrient content and uptake of nutrients, followed by coir pith, poultry manure and well rotten cow dung. Use of vermicompost medium without any additional growth regulators was sufficient to accelerate seedling growth in the nursery. When coir pith compost, poultry manure or well rotten cow dung was used in the medium, growth regulators had specific effect. Along with coir pith compost, IAA 300 ppm, BA 200 ppm and BA 300 ppm were ideal, while IAA 150 ppm, IBA 150 ppm and BA 300 ppm were superior with poultry manure medium. In normal potting mixture using cow dung, IBA 450 ppm, BA 200 ppm and IBA 300 ppm showed superiority. With the use of suitable media and growth regulators, seedling growth can be accelerated in the nursery and transplanting stage can be attained much earlier. Evaluation of different growth promoting substances in normal potting mixture showed that foliar spray of nutrient solution 3:1:1 (NPK) – 0.50 % (50 ml per plant) and Azospirillum sp. (10 g per plant) applied at fortnightly interval were the superior treatments with respect to all the growth parameters. In two year old grafted plants in the main field, a combination of GA 200 ppm + BA 100 ppm as bud application was the best with respect to majority of growth parameters, followed by GA 100 ppm + BA 100 ppm and GA 100 ppm. These growth regulators can successfully be used in early stages for promoting growth. In five year old juvenile orchard trees also GA and BA combinations, namely, GA 200 ppm + BA 100 ppm, GA 100 ppm + BA 100 ppm and GA 100 ppm + BA 200 ppm were the best treatments in accelerating growth and improving flushing. For the induction of flowering, soil drenching of paclobutrazol 2.0 g a.i. per tree, and bud application of GA 200 ppm + BA 100 ppm and GA 200 ppm + BA 200 ppm were superior and equally effective. For improving yield and yield attributes, paclobutrazol 2.0 g a.i. per tree was the most superior, followed by GA 100 ppm + BA 100 ppm and GA 200 ppm. Incidence of gamboge was minimum in paclobutrazol treatments, compared to GA, BA combinations. Among the various rootstocks tried, mangosteen was most compatible with its own rootstock where as all other rootstocks showed varying degrees of incompatibility. On comparing the growth of softwood grafts with seedlings, the latter showed faster rate of growth. Seedling growth could also be promoted by the use of nurse stocks. Large-scale multiplication of planting materials could be achieved through rooting of softwood cuttings from juvenile shoots of mangosteen. Seeds exposed to 5 Gy to 50 Gy gamma radiation showed wide variation in germination. Beyond 30 Gy, seeds failed to germinate. Seedlings from 30 Gy dose showed stunted growth indicating a possible genetic variation. Irradiation of scions with 5 Gy to 50 Gy had an adverse effect on days required for sprouting of scions, percentage of sprouting and final graft success. All the irradiated scions showed stunted growth even after one year. Two seedlings treated with colchicine at 3.0 and 3.5 per cent in the apical bud showed vigorous growth and distinct variation in growth characteristics. Five mangosteen seedlings with induced variations selected from irradiation and colchicine treatments were subjected to RAPD analysis. Clustering of five variants based on dendrogram separated the genotypes into two groups. Clustering pattern indicated that seed irradiation with 25 Gy and 30 Gy gamma rays and bud application of colchicine 3.5 per cent were effective in inducing variation in genomic DNA of mangosteen.
Open Access
Regulation of flowering in phalaenopsis orchids
(Department of Pomology and Floriculture, College of Horticulture, Vellanikkara, 2012) Kaveriamma, M M; KAU; Rajeevan, P K

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