Sweet orange. (Citrus sinensis (L.) Osbeck) is grown under both subtropical and tropical conditions. Dry and arid conditions, coupled with distinct summer and winter having low rainfall, are most favourable to the growth of the sweet orange. Rainfall seems to be unimportant if irrigation is provided, but atmospheric humidity exerts a great influence.
The sweet orange can be grown on a wide range of soils, from heavy clays to very light sands, with pH ranging from 6.0 to 8.0. The tree is particularly sensitive to high concentrations of salts and cannot stand water-logging.
VARIETIES. The important varieties of sweet orange grown in each region are 'Blood Red', 'Pineapple', 'Hamlin', 'Jaffa' and Valencia Late' in northern India, mosambi in Western India and 'Sathgudi' and 'Batavian' orange in southern India.
PROPOGATION AND PLANTING. Usually, propagated by budding. The most suitable rootstock is Jamberi or jatti khatti. For 'Pineapple', 'Hamlin', 'Jaffa' and 'Valencia Late' varieties, kharna khatta also provide a suitable rootstock. The trees are planted 6 to 7.5 metres apart each way in January or August-September in the north and in July-August in the south. The bud-union should be kept at least 15 cm above the ground while planting.
PRUNING. The pruning of citrus-trees begins in the nursery. All branches that start within a few centimetres of the union are removed, leaving about a half a metre of clean straight stem with a few well-placed branches. All unwanted branches are removed once a month during the first year after planting, and once in two to three months in subsequent years.
The bearing trees require little or no pruning. After the crop is picked, the branches touching the ground should be cut close total the laterals so that no stubs are formed. All diseased, injured and crossing branches, water-sprouts and dead wood should be removed periodically.
ROOT EXPOSURE In the Bombay-Deccan region, root exposure is given to the trees to bring them into flowering at a particular time of the year. Water is withheld for about two months in advance of the normal flowering season, and after about a month, the roots are exposed by removing about 10 cm of the soil in the case of light soils and about 20 cm in the case of heavy soils. After about 10 days, the soil is returned mixed with manure, and a light irrigation is given. After four or five days, a more copious watering is given, followed by 10 days later by the full dose of water. In the case of light soils, the withholding of water without root exposure is sufficient to check vegetative growth and force blossoming.
In southern India, no root exposure is given nor is it feasible. In the north, the root-exposure treatment is not necessary as the trees normally rest in winter and flower once a year. It should be mentioned that in most situations, the root exposure of citrus trees is a devitalizing process and should be resorted to only under expert advice and direction.
MANURING. Manuring may be followed as in the case of the santra orange.
IRRIGATION. After the first heavy irrigation given soon after planting a second light watering follows in four to five days. Thereafter, irrigation is given at regular intervals, depending upon the source of water and the nature of the soil. Under well irrigation, water is given after every eight days in hot months and about 12 to 15 days in cold months. Where irrigation is from canals, the usual interval is about 14 days. A light soil requires irrigation more often than a heavy soil. Excess watering should be avoided, especially in heavy soils.
When the trees are young, irrigation water is applied in basins of about one-metre radius. The basins are enlarged as the trees advance in age. In the ring method of irrigation a bund is formed about three-fourths of a metre away from the trunk to prevent water from touching it. The furrow method ensures a more even distribution of moisture in the soil.
HARVESTING. Trees begin to bear fruits from the fourth year onwards, but normal crops are borne from the seventh year. The main harvesting season in the north is December to February, whereas in the south, it is October to March. In the Bombay-Deccan region, there are two main seasons, November to January for ambe bahar, and March to May for mrig bahar
Picking may be done any time during the day, taking care that the stem is cut close to the fruit without damaging the rind. The fruits are washed, dried and graded for size and packed into wooden cases for disposal.
Grape. Grape (Vitis vinifera L.) is a subtropical fruit which grows well in dry climates having a short sharp winter and a long dry summer. The vines shed their leaves and rest in winter, put forth new growth in spring and mature in summer. Grape does not thrive in regions having humid summers. It tolerates frost during the resting period, but succumbs to it readily during its growing period. In India, however, it grows under varying climatic conditions. In Punjab, Uttar Pradesh and Himachal Pradesh, it grows and fruits once a year in summer, and rests during winter. In southern India, where it is cultivation mainly in Maharashtra, Hyderabad-Deccan, parts of Karnataka and Tamil Nadu, the vine grows throughout the year and bears two crops, the first in April and the second in August-September.
The grape grows best on light, friable loamy soils with free drainage. Heavy soils are unsuitable.
VARIETIES. Varieties suitable for different regions of the country are :
1. Northern plains : 'Black Prince', 'Bedana', 'Foster's seedling', 'Kandhari Dakh' and 'Muscat of Alexandria' , 'Perlette'.
2. Dry and temperate regions : 'Thomson Seedless', 'Sultana' and 'Kishmish White'.
3. Southern plains : 'Bangalore Blue', 'Pachadraksha' and 'Anab-e-Shahi', 'Gulabi', 'Black Champa', 'Thompson Seedless'.
4. Western plains : 'Cheema Sahebi', 'Anab-e-Shahi', 'Thompson Seedless'.
PROPAGATION AND PLANTING. The vine is usually propagated by cuttings. In northern India, cuttings are made from one-year-old wood at the time of pruning in February, when the vines are dormant. The cuttings are tied in bundles and stored in moist sand for about a month for callusing. The callused cuttings start well in the nursery. Elsewhere in India, they are obtained from the prunings in October and planted in nursery for rooting. The cuttings are ready for transplanting in January. It is also possible to raise a plantation by planting cuttings in situ in the field.
PLANTING. The rooted cuttings are transplanted in northern India in January and February when they are dormant. The planting-distance varies according to the method of training involved. It is 2.5m X 3.0m, if vines are trained on the head system and 6m X 6m, for the overhead pergola. In western India, it is 25m X 1m for the avenue system. in Karnataka, it is 4.5m X 6m and in Tamil Nadu 4.5m X 7.5m for the overhead arbour system.
