Navigation Links
Good parents are predictable -- at least when it comes to corn
Date:1/15/2012

In order to breed new varieties of corn with a higher yield faster than ever before, researchers at the University of Hohenheim in Stuttgart, Germany, and other institutions are relying on a trick: early selection of the most promising parent plants based on their chemical and genetic makeup, as well as on new statistical analysis procedures. The work has now been published in the authoritative journal Nature Genetics on Sunday evening, Jan. 15.

The problem is the sheer number: In the family tree of modern-day corn, there are two main groups with 10,000 pure-breed lines each. Each of these lines could potentially be used for producing a new variety by means of cross-breeding. In mathematical terms, that equates to 100 billion possibilities. In terms of corn, however, a parent's performance is no indicator of what potential lies hidden in their offspring. Even the feeblest of parents can produce mighty offspring when cross-bred.

But time is of essence: Currently it takes approximately 10 years for breeders to develop a new variety. Issues such as climate change, food shortages and the increasing demand for more energy, however, are making it essential to find solutions even faster.

Prof. Dr. Albrecht Melchinger, PhD student Christian Riedelsheimer and their research partners are experimenting with a new technique to solve both problems. The best parent plants are selected in two steps, beginning when they are not even planted yet or when they are just small plantlets. This saves time and guarantees the highest rate of success right from the very start.

Trick Nr. 1: Use mathematics and experience when selecting

Riedelsheimer takes a tiny sample from a kernel of corn. Not enough to harm the kernel, but enough to get a full picture of its DNA structure. This analysis is conducted jointly by the University of Hohenheim and the IPK Gatersleben.

The rest is mathematics and experience. "We know today that there is no single gene which determines whether a stalk of corn will grow up strong or produce lots of kernels on the cob. Instead there are numerous sequences in its DNA which all contribute to the plant's development. We can now examine up to 56,000 of these sequences using the latest techniques in genome analysis", Riedelsheimer explains.

The analysis does not involve modifying the DNA, but rather creating a unique profile of each parent, a so-called "genome profile" or "genetic fingerprint".

To analyse the fingerprint, scientists have spent the past three years and more planting, cross-breeding, analysing chromosomes and recording yields. The observations in the field have been used to develop a mathematical-statistical model which can be used to predict a parent's genetic potency.

Trick Nr. 2: Early selection

The composition of the leaves is a second indicator of which plants make for especially good parents. More specifically, it is about the amounts of starch, sugar, amino acids, chlorophyll and other substances. As with the genetic information, this data allows for a statistical prognosis of a plant's breeding capabilities.

Tests can be conducted to find out the levels shortly after the seeds have been sown, when the plantlets are roughly three weeks old and 20 cm tall. Compared with analysing the plant's genetic structure, taking samples in the field is rather an athletic activity. "The plant's metabolism varies constantly throughout the course of a day and that makes it necessary to collect the leaves quickly and shock freeze the samples immediately", says Riedelsheimer. "All in all we collected 6,000 samples- in just 69 minutes!"

For the technically-challenging task of analysing the substances, plant breeders work in collaboration with experts from the Max Planck Institute for Molecular Plant Physiology in Golm. The rest involves cutting-edge statistics. "Similar to the DNA profile, it is not the individual substances which are important for making predictions, but rather how these substances stand in relation to one another", Riedelsheimer explains.

New technology saves time, money and expensive acreage

"This new technique allows us to select the most promising parents with high accuracy and to focus all of our resources on these", says Prof. Dr. Melchinger.

This method also saves cultivatable land, which, in turn, saves money. "In order to test all possible crosses, we would have to plant corn on half of the earth's surface", a utopian, if not an expensive undertaking. "A single field plot costs us 50 euros. We test on two plots per genotype at ten different locations, making a total of 1,000 euros", Prof. Dr. Melchinger explains. An analysis of the genome using a chip and a robot costs approximately 150 euros.

Impressive as well is the amount of time saved. DNA analysis of the kernels can be conducted during the winter months. Meanwhile, the plantlets to be analysed for their substance composition grow in the greenhouse. As a result, the best parent plants can be chosen and cultivated that same year.

Paradigm shift opens door to new research approaches

Nonetheless, it will take another few years until the new breed is ready. Breeders worldwide also know another trick, especially when it comes to corn. One that has been around for decades.

Prof. Dr. Melchinger describes a paradoxical phenomenon: "With corn, the offspring tend to be especially large when the parents stem from generations of in-breeding." Experts speak of "heterosis", hobby gardeners of "hybrids".

The most promising parent plants are sorted out and self-pollinated over many generations. Only then does cross-pollination take place in preparation for the sowing of the new hybrid variety.

Heterosis as a biological phenomenon has yet to be fully researched in detail, according to Prof. Dr. Melchinger. "We were able to determine in earlier research projects that the reasons for the phenomenon lie in the extremely complex interaction of many different genes."

For researchers, this has led to a paradigm shift. "We've moved away from the search for individual super genes." Instead we focus on the interplay among the diverse elements in the genetic code. "This new perspective on plants will help the hybrid breeding programme immensely", Prof. Dr. Melchinger believes. "There is so much genetic diversity in corn. One must simply know how to combine it in the right way."


'/>"/>

Contact: Albrecht E. Melchinger
melchinger@uni-hohenheim.de
49-071-145-922-3488
University of Hohenheim
Source:Eurekalert  

Related biology news :

1. Study reveals gender bias of prospective parents
2. Research aims to prevent obesity by reaching parents, young children through child care
3. Parents feel shock, anxiety and the need to protect children with genital ambiguity
4. Parents stress leaves lasting marks on children’s genes: UBC-CFRI research
5. Mutations not inherited from parents cause more than half the cases of schizophrenia
6. Opposites may attract, but they dont make better parents
7. Parents social problems affect their children -- even in birds
8. Study recommends that parents, physicians share decisions in sex development disorder surgery
9. Penguin males with steady pitch make better parents
10. Doctors can influence when parents wean children from bottle, study finds
11. UNC study: Color-coded chart improves parents understanding of body mass index
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Good parents are predictable -- at least when it comes to corn
(Date:6/22/2016)... ANGELES , June 22, 2016 /PRNewswire/ ... identity management and verification solutions, has partnered ... edge software solutions for Visitor Management, Self-Service ... provides products that add functional enhancements ... partnership provides corporations and venues with an ...
(Date:6/21/2016)... Columbia , June 21, 2016 ... to the new role of principal product architect ... named the director of customer development. Both will ... chief technical officer. The moves reflect NuData,s strategic ... in response to high customer demand and customer ...
(Date:6/16/2016)... , June 16, 2016 ... is expected to reach USD 1.83 billion by ... View Research, Inc. Technological proliferation and increasing demand ... are expected to drive the market growth. ... The development of advanced multimodal techniques ...
Breaking Biology News(10 mins):
(Date:6/27/2016)... June 27, 2016 /PRNewswire/ - BIOREM Inc. (TSX-V: BRM) ("Biorem" ... by its major shareholders, Clean Technology Fund I, LP ... States based venture capital funds which together ... (on a fully diluted, as converted basis), that they ... their entire equity holdings in Biorem to TUS Holdings ...
(Date:6/27/2016)... ... June 27, 2016 , ... Rolf K. Hoffmann, ... faculty of the University of North Carolina Kenan-Flagler Business School effective ... at UNC Kenan-Flagler, with a focus on the school’s international efforts, leading classes ...
(Date:6/24/2016)... , ... June 24, 2016 , ... While the majority ... as the Cary 5000 and the 6000i models are higher end machines that use ... height of the spectrophotometer’s light beam from the bottom of the cuvette holder. ...
(Date:6/23/2016)... 2016 /PRNewswire/ - FACIT has announced the creation ... biotechnology company, Propellon Therapeutics Inc. ("Propellon" or "the ... a portfolio of first-in-class WDR5 inhibitors for the ... WDR5 represent an exciting class of therapies, possessing ... for cancer patients. Substantial advances have been achieved ...
Breaking Biology Technology: