Fruit Crops Questions and Answers

Answer: B

Conference is the best polliniser for William and Bartlett pears, according to the key. A polliniser must flower at the same time and give compatible pollen.

I could not confirm this from a source. California Advance, Manchurian and Non-Pareil are the other options and the key does not give them.

Pear flowers need cross-pollination, and the polliniser must flower at the same time as the main variety and be compatible with it. The key names Conference as the best polliniser.

Answer: A

The key gives Dashehari for the dehorning technique at GBPUAT, Pantnagar. In dehorning, the shoot tip is removed to force new growth for flowering in mango. I could not find a source to confirm the variety, so this rests on the key.

Langra, Chausa and Krishnabhog are other north Indian mango varieties.

The key names Dashehari for dehorning at Pantnagar. Dashehari is a popular north Indian mango and shows alternate bearing, which pruning aims to correct.

Answer: B

Cauliflory is the bearing of flowers and fruits on the trunk and old branches. Cocoa is the standard example, with pods borne straight on the trunk.

Coffee bears fruit on branches, palmyrah on a crown, and cashew on twig tips.

Cauliflory is shown by cocoa, jackfruit and some other tropical trees. Flowers arise on the main trunk or the thick branches, not at the twig tips.

Answer: D

Citrus breeding was first carried out by W. T. Swingle and H. J. Webber, who in the United States produced hybrids such as the tangelo and citranges. This is the key's answer.

The other names are workers on other topics or in other places.

Swingle and Webber worked at the US Department of Agriculture and are known for early citrus hybrids, such as the citrange. The key names them for the first breeding work.

Answer: A

The mango variety exported most from India is Alphonso.

Alphonso, grown mainly in the Ratnagiri and Sindhudurg districts of Maharashtra, is prized abroad for its colour, aroma and keeping quality, and it makes up the largest share of India's fresh mango exports, going to the Gulf, Europe and other markets.

Langra and Chausa are popular north Indian varieties sold mostly in the domestic market, and they do not travel as well. Gaurjeet is a regional variety of eastern Uttar Pradesh with little export trade.

Answer: A

Fruit cracking in pomegranate is due to deficiency of Boron.

Fruit cracking is a serious disorder of pomegranate, especially in dry areas. It is linked to boron deficiency, which weakens the cell walls of the rind, together with sudden changes in soil moisture, such as heavy irrigation or rain after a dry spell. It is controlled by spraying borax and by regular, even irrigation.

Calcium also affects rind strength, but boron is the deficiency the standard recommendations name. Iron and copper deficiencies cause other symptoms, such as yellowing of leaves.

Answer: C

Pre-harvest fruit drop in apple is due to hormonal imbalance.

As apple fruits approach maturity, auxin production in the fruit falls while ethylene rises. This change triggers formation of the abscission layer in the stalk, and fruits fall before they can be picked. It is controlled by spraying the auxin NAA (naphthalene acetic acid) a few weeks before harvest, or by inhibitors of ethylene synthesis.

Insufficient pollination and embryo abortion cause early drop of young fruitlets, not drop just before harvest. Moisture stress can make it worse, but the underlying cause named in standard texts is the hormonal change.

Answer: B

Black heart is a physiological disorder of Pineapple.

Internal browning, called black heart, develops when pineapple fruits are exposed to low temperatures, during cool nights in the field or in cold storage, and then brought to warmer conditions. The flesh around the core turns brown to black while the outside looks normal. It is a form of chilling injury.

The main disorders of the other fruits are different: guava has fruit cracking, mango has spongy tissue and malformation, and cherry is known for fruit cracking. None of them is known for black heart.

Answer: D

Granulation is a physiological disorder of Citrus.

In granulated fruits the juice vesicles become hard, enlarged, dry and greyish, so the fruit has little juice and poor flavour. It is common in sweet orange and mandarin, especially in large fruits on young, vigorous trees and in fruits left on the tree after maturity.

The other fruits have different disorders: guava suffers from fruit cracking and bronzing, papaya from bumpy fruit (a boron deficiency), and mango from spongy tissue and malformation.

Answer: B

The trait is associated with M. balbisiana.

Cultivated bananas descend from two wild species, Musa acuminata (the A genome) and Musa balbisiana (the B genome). The B genome contributes hardiness: greater tolerance of drought and cold and resistance to some diseases. That is why ABB and AAB cooking and dessert types such as Monthan and Poovan are hardier than the pure AAA dessert bananas.

M. acuminata contributes sweetness and dessert quality rather than hardiness. M. laterita and M. ornata are ornamental species that are not parents of cultivated bananas.