(HT-213) physiological disorder Of Tomato.pptx

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1. PHYSIOLOGICAL DISORDERS OF TOMATO

2. Physiological disorder is the abnormal growth pattern or abnormal external or internal conditions of fruits due to adverse environmental conditions such as deviation from normal state of temperature, light, moisture, nutrient, harmful gases and inadequate supply of growth regulators . Fruit cracking Blossom end rot Sun scald Puffiness Cat face Unfruitfulness

3. Fruit cracking Two types of fruit cracking are seen. Radial cracking , where surface of the mostly full ripe fruits cracks radically from the stem end of the fruit. Concentric cracking , where surface of mostly mature green fruits cracks concentrically around the shoulder of the fruit . Radial cracking is more common and causes greater loss than concentric cracking.

4. Cracking may occur due to- i ) Irrigation or rainfall after long dry spell. ii) Exposure of fruits to sun due to pruning and staking. iii) Boron deficiency. iv) Genetic factor which is reported to be inherited polygenically . Control Irrigation at regular intervals Pruning and staking during summer season should be avoided Picking of fruits before fully ripe stage which reduces radial cracking Spraying seedlings before transplanting with 0.3-0.4% borax solution and repeating the sprays at the time of fruiting, 15 days after second spray and at fruit ripening stage Growing resistant varieties like Sioux, Roma, Punjab chuhara , pusa ruby, Arka saurabh , Pant T1 etc.

5. Blossom end rot Brown water soaked discoloration appears at the blossom end of the fruit where the senescent petals are attached while the fruit is still green. The spots enlarge and darken rapidly and the affected portion of the fruit becomes sunken, leathery and dark coloured .

6. This disorder may occur due to – Sudden change in the rate of transpiration specially in moisture stress condition Continuously high evapotranspiration regime and a large leaf area Increasing level of nitrogen content in the fruits. Control This disorder is decreased by increasing the frequency of irrigation Judicial fertilizer application . Increase in the level of phosphate fertilization application decline the incidence of this disorder. Liming decreases the incidence Single foliar spray of 0.5% calcium chloride (CaCl2) at the time of fruit development.

7. Sun scald Exposed portion of either green or nearly ripe fruits get blistered and water soaked due to extreme heat of scorching sunshine. Rapid desiccation in the blistered portion turns the sunken areas white or grey in green fruits and yellow in pink or red fruits. Sun scalding may cause inhibition of fruits softening, production of tough tissues and differential fruit ripening.

8. This problem is common in plants that have lost considerable foliage. For this reason, training and pruning in tomato aggravate this disorder because foliage cover over the fruit is reduced in these cultural practices. Cultivars with heavy foliage cover are least affected by this disorder. Control 1) Protection of plants from defoliation by diseases and insect pests 2) Training and pruning in summer months should be avoided

9. Puffiness Outer wall of the grown up fruits (two-third normal size) continues to develop normally but growth of the remaining internal tissues (Placenta, mesocarp ) is retarded resulting in partially filled fruit which is light in weight and lacks in firmness. Cross section of the affected fruit shows emptiness or pockets. The differential tissue growth leading to this disorder.

10. This disorder occurs due to i ) Non fertilization of ovules ii) Embryo abortion after normal fertilization iii) Necrosis of vascular and placental tissue after normal development of the fruit iv ) High temperature and high soil moisture are the primary factors responsible for this disorder. Control Application of boron reduces puffiness and improves fruit shape. Over irrigation should be avoided. Less nitrogen should be applied. Boron should be applied by spraying 0.3-0.4% borax solution.

11. Cat face Distortion of the blossom end of the fruit gives rise to various ridges, furrows and indentation in a localized area of the fruit. Cat face is named due to these ridges and indentations . Abnormal growing conditions during formation of the blossoms appear to cause death of the cells of the blossom end of the ovary which turn dark to form a leathery blotch at the end of the fruit. Unlike blossom end rot, the patch does not progress and thus gives rise localized affected area.

12. Unfruitfulness Temperature particularly a night temperature has profound effect on fruit setting in tomato. High day temperature ( above 32 °C ) and high night temperature ( above 20 °C ) is not congenial to fruit set. On the other hand fruits normally fail to set at or below 13°C . Both high and low temperature adversely affects fruit set mainly by reducing pollen viability and pollen germination on stigma. For this reason, low fruit set is a problem during summer cultivation in eastern India, especially in West Bengal where temperature remains above critical limit and during winter cultivation in northern India where temperature falls far below the critical level in winter.

13. Control: Growing high temperature tolerance verities ex: Hot set , HS-102 , Pusa Hybrid-1 and Punjab chhuhara . Use of low temperature tolerance verities ex: Cold set , Pusa Sheetal . Spray crop with Parachlorophenoxy acetic acid (PAPC) @ 50 PPM at full blome stage and 2,4-D @ 1-2 ppm before anthesis and 14 days after first spray.