3.7 ORCHARD MANAGEMENT PRACTICES
3.7.1 Performance of Sweet Orange cv. Mosambi on Different Rootstocks
The performance of sweet orange cv. Mosambi budded on five different rootstocks was evaluated under Delhi conditions. Plant height, canopy spread, fruit weight, yield
Performance of wheat under organic conditions
Treatment Plant height Number of 1000- seed Seed yield
spikes/m. weight (t/ha) row
FYM in both rice and wheat 88.6 73.0 50.9 3.51
FYM in rice only 87.1 68.5 51.1 2.99
FYM in rice + rice straw in wheat 85.5 60.7 51.6 2.79
FYM in both rice and wheat+straw 89.5 78.0 51.3 3.48
GM in rice+FYM in wheat 79.2 60.7 50.7 2.66
GM in rice only 74.3 40.5 50.8 2.28
GM in rice+ rice straw in wheat 78.3 48.0 49.2 1.87
GM in rice+FYM in wheat+straw 82.0 66.5 50.1 2.33
Recommended fertilizers (NPK 120:60:30) 87.8 92.2 44.6 3.47
CD (P=0.05) 2.08 11.9 1.58 0.74
and juice recovery were noted maximum on Mosambi plants raised on Karna Khatta rootstock while plant height and canopy spread were observed minimum on Cleopatra Mandarin. Rootstocks also influenced fruit quality of Mosambi.
The maximum T.S.S. and ascorbic acid contents with lowest acidity were noted on Cleopatara Mandarin rootstock. Data also revealed that Karna Khatta rootstock had maximum potassium, zinc and iron contents in the leaves followed by Soh Sarkar while these were minimum on Cleopatra Mandarin
rootstock. Observations on initiation of flowering in Mosambi budded on different rootstocks clearly indicated early flower initiation on Soh Sarkar roostock. However, late flowering was noticed in Cleopatra Mandarin rootstock.
3.7.2 Salt Tolerance Studies in Citrus
Six genotypes of citrus, namely, Jatti Khatti, RLC 1, RLC 2, RLC 5, RLC 7 and Attain 1 were screened against different levels of NaCl stress. Results revealed that among six genotypes, Attani 1, RLC 1 and RLC 7 withstood salinity up to 1.95 dS/m and other genotypes failed to survive even at low level of salinity (0.98dS/m). Among three salt tolerant genotypes, minimum reduction in plant height (50.61%), root length (5.07%), dry weight of shoot (70.72%), roots (70.75%) and RWC (9.30%) was recorded in Attani 1 at higher salinity level suggesting that Attani 1 was more tolerant than RLC 1 and RLC 7 to salinity stress.
Growth, yield and quality parameters of ‘Mosambi’ sweet orange on different rootstocks Rootstock Plant Spread (m) Fruit Fruit Juice T.S.S. Acidity Ascorbic
height (m) E-W N-S yield weight yield (%) (%) acid
(number/ (g) (%) (mg/ 100
juice) Soh Sarkar 2.98 3.45 3.40 64.16 186.33 46.25 10.20 1.03 42.87 Jambhiri 2.73 3.62 3.45 52.50 182.25 43.25 10.10 1.09 41.55 Mosambi 2.86 3.33 3.10 73.20 183.16 44.89 10.10 1.04 43.08 Karna Khatta 3.57 3.66 3.84 86.20 193.16 48.46 10.20 1.04 43.56 Cleopatra 2.55 3.16 3.25 68.25 180.25 47.37 10.25 1.02 44.49 Mandarin
3.7.3 Effect of Paclobutrazol on Citrus Rootstocks under Salt Stress
Analysis of data showed that NaCl with paclobutrazol (PBZ) treatment affected growth parameters. All growth parameters decreased in NaCl stressed plants of the rootstocks Soh Sarkar and Rangpur Lime. However; the rate of reduction was different.
Application of PBZ at 250 ppm was found to be effective in mitigating the salinity stress in salt susceptible rootstock Soh Sarkar. However, paclobutrazol when applied at 125 ppm improved the stress tolerance in salt tolerant Rangpur Lime. All growth variables increased with the application of PBZ in both the rootstocks.
Application of 250 ppm PBZ increased the height by 34.47% in Soh Sarkar and 14.98% in Rangpur Lime.
However, per cent increase in leaves/plant was higher (170.61%) in Soh Sarkar salt stressed plants treated with 250 ppm PBZ than in plants from salt stress without PBZ.
Root length also varied significantly in different treatments. In Soh Sarkar, maximum increase in root length (51.18%) was recorded when salt stressed plants were treated with 250 ppm PBZ, while in Rangpur Lime maximum increase in root length (68.40%) was found with the application of 125 ppm PBZ under salt stress.
Root to shoot ratio increased with the application of PBZ, and maximum increase (35.30%) was recorded with the treatment of 250 ppm PBZ in Soh Sarkar, whereas in Rangpur Lime, maximum increase (24.32%) was measured with 125 ppm paclobutrazol. Membrane injury index (MII) reduced with the increasing concentration of
paclobutrazol, and lower MII was recorded with the application of 250 ppm PBZ in Soh Sarkar (0.253) and in Rangpur Lime (0.131) as compared to that in salinized plants (0.317 in Soh Sarkar and 0.272 in Rangpur Lime) without PBZ treatment.
3.7.4 Studies on Mango Malformation
18.104.22.168 Antifungal activity of datura, calotropis and neem
To isolate the biologically active part of plant, different aerial parts (leaf, stem, flower, fruit and seed) of datura, calotropis and neem were air dried, powdered and then extracted in methanol using Soxhlet apparatus for 72 hours.
In vitro culture of the malformed tissues in MS media along with different plant extracts revealed differential capacity to suppress the growth of Fusarium mangiferae.
In treatment where methanol and chloroform extracts of datura (leaves and seeds) and calotropis (leaves) were mixed and used, the mycelial growth was restricted to the surface of the explant only, and no fungal growth was observed in the media when compared with all other treatments.
22.214.171.124 Field trial with brewed tea spray
A slurry was prepared by mixing 100 g of well-rotted cow manure and fresh parts of datura (100 g leaves, 100g seeds) and calotropis (100 g leaves) in 15 liters of water. The slurry was allowed to brew for 15 days under continuous aeration by using an air pump, and then filtered by using a muslin cloth.
The filtrate, which was richly-coloured and odorless, was used immediately for spraying without further dilution.
Since Fusarium mangiferae infects the sprouting buds, to induce the symptoms of malformation, the brewed tea was sprayed on the mango trees at flower bud sprouting stage, at fruit set stage, and in June-July on the newly emerged malformed panicles to see its effect on malformation. The results were compared with foliar spray with bavistin (1%, 2% and 10%). The control of malformation was found best (100%) in trees sprayed with brewed tea when compared with bavistin (1%, 2% and 10%).
126.96.36.199 Modelling epidemiology of Fusarium mangiferae in relation to mango malformation
Data related to intensity of mango malformation, number of colonies of Fusarium mangiferae per gramfresh weight of mango bud, and weather variables at selected malformation
Effect of salt and paclobutrazol on root:shoot ratio of citrus species
prone and free areas in India were collected. They were analyzed for their relation and for developing and validation of Multiple Linear Regression prediction models. The results were confirmed with logistic regression model by using SPSS and GIS tools for two different states, namely, Andhra Pradesh and Uttar Pradesh, which differed significantly in malformation intensity. The relationship was verified between independent and dependent variables by multiple correlation analysis.
Mango malformation showed positive correlation with the number of colonies of Fusarium mangiferae g-1 fresh weight of mango bud
Among the weather variables, wind speed and RH2 showed the highest degree of positive association with the number of colonies of Fusarium mangiferae g-1 fresh weight of mango bud
Out of five weather variables, maximum temperature and RH were found to be the determining factors for occurrence of mango malformation
Weather in the initial month of flowering period (i.e., November in AP and February in UP) were found to be most responsible for mango malformation incidence
The developed model correctly predicted the differential occurrence of malformation in UP and AP. The conditions for the development of Fusarium were found to be favourable only in certain pockets of north western AP, particularly in the districts of Medak, Rangareddy, Hyderabad and (part of) Adilabad. The remaining districts of AP are relatively free from the disease
The weather conditions for the development of Fusarium were found favourable in the entire state of UP.
GIS tool was found to be very useful for the prediction of spatial distribution of mango malformation at regional scale by using geo-statistical, multiple criteria analysis and logistic regression approach, which otherwise could have been impossible.
3.7.5 Organic and Biofertilizer Studies in Mango
An experiment was conducted to examine the effect of FYM, vermicompost, Azotobacter, Azospirillum and mixed strain of AM fungi (nutrilink), and phosphate solublising bacteria (Microphos) on plant growth, assimilate partitioning, leaf nutrient status, fruit yield and quality in mango cv.
Amrapali. The experiment was laid out in a randomized block
design comprising 13 treatments with four replications.
Treatments given were T0 : Control (no compost or fertilizer), T1 : Farm Yard Manure alone (FYM), T2 : vermicompost alone (VC), T3 : FYM + VC, T4 : FYM + VC + Azotobacter (AZR), T5 : FYM + VC + phosphate solublising bacteria (PSB), T6 : FYM + VC + AM fungi, T7 : FYM + VC + AM fungi + AZR, T8 : FYM + VC + PSB + AZR, T9 : FYM + VC + AM fungi + AZR + Azospirillum(AZM), T10 : FYM + VC + PSB + AZM + AZR, T11 : FYM + VC + AM + PSB + AZR + AZM, T12 : 20 kg FYM + NPK. Treatments were given on the basis of total nitrogen requirement (500 g/plant/year) of the plants, i.e., FYM- 100 kg to T1 and 50 kg/plant to all treatments except T0, T2 and T12, and vermicompost -33 kg to T2 and 16.5 kg per plant to all treatments except T0, T1 and T12. Two kilogram neem cake was uniformly applied to each treatment. All biofertilizers were applied @ 10 g per plant, while AM fungi @ 20 g per plant was applied during August- end and the last week of February. For analytical procedure and observations on growth parameters, assimilate partitioning, leaf nutrient status, fruit yield and quality, standard procedures were adopted. Among various growth parameters observed, the increase in plant height and canopy volume was found significant, whereas the increase in trunk girth and plant spread (East- West and North- South) was found non-significant. Maximum increase in plant height was observed in T9 (9.1 per cent), which was closely followed by T8, T10 and T11. Application of biofertilizers along with FYM and vermicompost showed better results as compared to control, FYM and vermicompost alone. Assimilate partitioning and other physiological parameters such as photosynthesis rate and leaf nutrient status were significantly higher as compared to control, and full dose of N application.
Leaf nutrient status was found significant for N, P, Ca, Mg, Fe, Cu and Zn as compared to control. The treatment comprising FYM (50 kg), vermicompost (16.5 kg), Azotobacter (10g) and PSB (10g) per plant gave the best results for maximum average numbers of fruits (181.2) per plant, yield (33.4 kg per plant), TSS (23.0 %), β-carotene (15,867 µg/100g) and ascorbic acid (37.5 mg/100g pulp) content.
3.7.6 Nutritional and Physiological Studies in Citrus
In Kinnow mandarin, foliar spray of micronutrients, i.e., manganese, zinc, copper and iron each at 0.4% along with soil application of biofertilisers alone and in combined doses were tried. A common fertilization dose and biofertilisers,
namely, Azotobacter (10 g/plant) + PSB (10 g/plant) were applied uniformly to all treatments. The treatment comprising combined spray of Fe, Cu, B and Zn at 0.4% each was found superior for growth and yield (105 fruits /tree) parameters as compared to control (71.0 fruits/tree) and other treatments.
The maximum juice recovery (55.9 %) and TSS: Acid ratio (14:1) was also recorded in the above treatment.