Monday, December 3, 2012

Fruit Blog Entry #2

Genetically Modified Foods 

So…Questions to address:
1. What do you think about GM-foods?
(All opinions welcome!!)
2. Do you think GM foods should be labeled? 

Date: December 3rd, 2012
Why would you want to genetically modify a fruit or vegetable?

We modify fruits and vegetables to make them superior than the original ones. Also, we modify them for convenience to fit our needs. For example, in the past a bag of rice would spoil sooner than the rice we have nowadays. This is because the present rice is genetically modified. It is more resistance to the environment than the rice from the past. Leading it to last several weeks longer than the rice we had before. Also, we modify fruits and vegetables for aesthetics reasons. When people go to the fruit market or supermarket, they always go for the fruits or vegetables that look very colorful and pretty because people assume that those vegetables and fruits are the best. The others that look opaque are left on the counters to perish because they don’t look good. Also, we do genetically modify crops to feed large amount of people with the goal to control hunger.

1. What do you think about GM-foods?

GM-foods offer us a greater quality because they are selected from the best traits from the true to types. Plant breeders select them based on the best genotypes and phenotypes available after they test them. Eating GM-foods should not be avoided after all we are not eating harmful chemicals present in our foods. We are just eating products with different genetics traits, which could have happen in our environment by accident anyways. We are just accelerating the process of nature. Instead of waiting for nature to select the best traits to that the surrounding can offer, we do it ourselves while in the process selecting the best genes that adjust to our needs. In brief, we are not eating anything harmful with GM-foods, but instead we are consuming crops that possess the best out of the best.    

2. Do you think GM foods should be labeled? 
Yes, they should be labeled. By labeling them, they show to the public the truth. In case in the future there are harmful discoveries towards some GM products, which is unlikely to happen in my opinion, people know what they have been consuming. Also, there are people who don’t want to consume GM-foods, so by labeling them, those people get the freedom that they deserve to choose whether or not the food they eat is GM-foods. Also, labeling GM-foods should create more jobs which I see as a positive thing in our society.

Monday, November 19, 2012

Diseases and Pests of Fruit

November 19, 2012
 A pest is any organism that negatively directly or indirectly affects fruit quality either pre- or post-harvest. Pests that attack fruit crops include bacteria, mollicutes: (Bacteria without cell wall, phytoplasmas), fungi, insects, weeds, and nematodes.

Then we have bacterial diseases that can cause damage to fruit, leaves, and stems. They spread by tools, wind, rain, and labor. They can be control with genetic resistance, chemical sprays, which may not be very effective, and sanitation. 

Bacterial Diseases and the Fruits they affect:
  •  Fireblight – apples, pears
  •   Citrus canker, greening -oranges, grapefruit 
  •  Bacterial canker – peaches
  • Bacterial Leaf Spot
  •  Crown gall - apples, peaches, cherry, grapes

Fungal Diseases can affect leaves, fruit, stems, and roots. They spread by soil and aerial means (rain). They can be control with genetic resistance, fungicides, and biological ways (natural).
Important Fungal Diseases and the Fruits they affect:
  •  Black sigatoka – banana 
  •  Fusarium, many crops – bananas
  • Brown rot – peaches, citrus
  • Black rot/ripe rot (postharvest) – grapes
  • Scab – apple, citrus, peach
  • Powdery mildew (dry environment) – grapes, apples, chestnut, cherries
  • Wilt – grapes, blackberries, raspberries
  • Anthracnose – avocado, mango

Mollicutes are similar to bacteria, lack cell walls, and survive on inorganic sources. They have a life-like similar to bacteria, and decline symptoms similar to viruses.

Important Mollicute Diseases and the Fruits they affect:
  • Witches Broom – Limes
  •  Stubborn Disease (spiroplasma) – Oranges
  • Pear decline
  •  Lethal Yellows (phytoplasma) – Coconut
  •  Grapevine Yellows

Virus Diseases are the most severe of all diseases. They spread by budwood, budding, grafting, insects, mites, nematodes, and pollen. They can be control with genetic resistance and heat therapy.

Important Virus Diseases and the Fruits they affect:
  • Citrus Tristeza: (mites)
  •  Apple Mosaic – apples, peaches (pollen)
  •  Papaya ring spot spread (Aphid)
  • Tomato ring spot - apple, stone fruits (Nematode)

Other Common Pests of Fruit Crops
  •  Insects
  •  Mites
  •  Animals – deer, moles/voles
  •  Snails

Pruning and Fumigation

November 14, 2012 

Pruning is the removal of a portion of a tree to correct or maintain tree structure. Training is a relatively new practice in which tree growth is directed into a desired shape and form. Training young fruit trees is essential for proper tree development. It is better to direct tree growth with training than to correct it with pruning.
As a principle of pruning, use sharp tools to make sharp cuts to avoid extended pieces of branch (nubs). It is not recommended to cut close to trunk instead make collar cut to avoid cracking the branch of the tree and there is no need to paint cuts.
Pruning is most often done during the winter, commonly referred to as dormant pruning. Training includes summer training and summer pruning as well as dormant pruning. The goal of tree training is to direct tree growth and minimize cutting.

Balance cropload and vegetative growth.
Improve light penetration.
Improve insecticide/fungicide efficacy.
Increase air movement.
Decrease disease.
Increase fruit size (Thin fruit buds, reduce yield)
Facilitate mechanical harvesting.

Fumigation is use to eliminate nematodes, replant disease and eliminate or reduce weed populations, which are all serious factors that inhibit the proper development of fruits crops.
Acute fumigant poisoning causes eye irritation, sore throat, headaches, nausea, vomiting, breathing difficulties and aggravated asthma, and neurological effects such as convulsions, dizziness, or tremors. Fumigant exposure also has long-lasting effects that include cancer, respiratory damage: Exposure to fumigants can cause permanent respiratory damage, neurological effects, reproductive & developmental effects, immune system effects, and endocrine disruption.

Soils for Fruit Crops

November 7, 2012
We learned about soil characteristics because people need to know the proper aspects of soils for them to grow their fruit crops. Some of those factors are pH of soil. pH can affect nutrient solubility. If pH is too high, it limits the macronutrients needed by the plants. Cation Exchange Capacity is the maximum quantity of total cations, of any class, that a soil is capable of holding, at a given pH value, available for exchange with the soil solution. CEC is used as a measure of fertility, nutrient retention capacity, and the capacity to protect groundwater from cation contamination.

Fertilizer Tests help to determine nutrient levels
Soil tests are the analysis of a soil sample to determine nutrient and contaminant content, composition and other characteristics, such as acidity or pH level. Tests are usually performed to measure the expected growth potential of a soil. They play a great role before growing a certain fruit crop.
We also talked about plant tests. Soil and herbage analyses help pastoral farmers and their advisers choose the best fertilizer programmed. They also highlight mineral imbalances that might be affecting the health of pasture or animals that feed on it.
Herbage tests of pasture complement soil tests and allow important trace nutrients like cobalt, selenium, copper and iodine to be adjusted for improved animal health. Using both herbage and soil testing will provide a better overall picture of the farm nutrient status for an improved fertilizer programmed.
Moreover, Fertilization Methods were addressed in class. They can be broadcast, which is when application is over entire orchard floor. Banding, it is applied within tree root zone. And fertigation is applied through irrigation system and delivered in small doses.

Fruit Quality and Dormancy

October 29 – November 2, 2012

We learned that the factors in fruit quality are size, shape, color, blemishes, and texture. Fruit Skin Blemishes are a problem because they affect marketability of fresh fruit. People’s perception towards fruit skin blemishes lead to a decrease of sales of the fruits affected by them. They biotic causes of fruit blemishes are insects, mites, bacteria, and fungi. Then we covered in class the abiotic causes were wind, hail, sunburn, and low or high temperatures.

Further, the fruit maturity factors. Fruits can be climacteric and Non-climacteric. Climacteric fruits refer to fruits that have high respiration rate during the fruit's ripening. During the ripening process of climacteric fruits, the production of a phytohormone, ethylene, dramatically increase up to 1000-fold of the basal ethylene level. Climacteric fruits are ones that are able to ripen after being picked. Examples of climacteric fruits are bananas, apples, pears, and avocados. On the other hand, Non-climacteric fruits are fruits that does not ripen after harvest. Examples of non-climacteric fruits are citrus, grapes, cherries, raspberries, strawberries and cashews.

Dormancy is a state of temporary metabolic inactivity or minimal activity. Plants generally go dormant in response to adverse growing conditions. For example: perennial plants going dormant for the winter or grass going dormant in intense heat. They stop growing and conserve energy until better cultural conditions present themselves. This happens naturally as seasons and weather changes. It can also be artificially controlled to store plants for shipping or to get them to flower for particular holidays. Forcing bulbs and flowering branches in the spring is a way of artificially breaking dormancy.
It's helpful to mulch over perennial plants, once the ground has frozen, to prevent them from breaking dormancy too soon.

Monday, October 29, 2012

Fruit Blog Entry #1

Questions to address:

1. Tell us what your favorite fruit is – and:
2. Where is it grown?  In the US? World?
3. What kind of fruit is it?  (Botanical description)
4. Attach a picture, from the supermarket (if it is being sold right now).

My favorite fruits are bananas. Bananas need a constant temperature, and also humidity levels. Both are found in tropical regions, as opposed to the cooler climates of North America and Central Europe.

The only states in the US to grow bananas are Hawaii and Florida, however the crops tend to be small, leaving the US dependent on imported bananas.

Botanical description
Bananas are large, herbaceous monocots, reaching twenty feet in some cultivars, but generally six to fifteen feet tall in cultivation. The "trunk" or pseudostem is not a true stem, but only the clustered, cylindrical aggregation of leaf stalk bases. Leaves are among the largest of all plants, becoming up to nine feet long and two feet wide. Margins are entire and venation is pinnate. Leaves tear along the veins in windy conditions, giving a feathered or tattered look. There are five to fifteen leaves on each plant, with ten considered the minimum for properly maturing a bunch of fruit. The perennial portion of the plant is the rhizome, which may weigh several pounds. It is often called a corm. It produces suckers, or vegetative shoots, which are thinned to two per plant - one "parent" sucker for fruiting and one "follower" to take the place of the parent after it fruits and dies back. It also produces roots and serves as a storage organ for the plant.

                                                     Picture of bananas in supermarket


October 19 - October 26, 2012

We talked about several concepts, but I focused on pollination because it seems to have caught my attention the most. Pollination is ransfer of pollen from the anthers of a flower to the stigma of the same flower or of another flower.  Pollination is a prerequisite for fertilization, which allows the flower to develop seeds. 
Some flowers will develop seeds as a result of self-pollination, when pollen and pistil are from the same plant. Other plants require cross-pollination and for this pollen and pistil must be from different plants.

When plants need help moving pollen from one flower to the pistil of another.  Wind moves the pollen for some plants such as grasses like corn.  Animal pollinators move pollen for many other flowering plants.

Pollinator is an animal that moves pollen from the anthers to the stigmas of flowers, thus effecting pollination.  Animals that are good pollinators of flowers include bees, butterflies, hummingbirds, moths, some flies, some wasps, and nectar feeding bats.   

Plants benefit from pollinators because the movement of pollen allows them to reproduce by setting seeds.  However, pollinators don't know or care that the plant benefits.  They pollinate to get nectar and/or pollen from flowers to meet their energy requirements and to produce offspring.  In the economy of nature, the pollinators provide an important service to flowering plants, while the plants pay with food for the pollinators and their offspring.