Winter Reading

[bower]

Thank you Chris!

[Fusion_power]

A good summary would be that hybrid tomatoes are more consistent than most open pollinated tomatoes. There are a few open pollinated varieties that outproduce almost all of the hybrids. The stabilized cross of Eva Purple Ball X Big Beef is highly productive. An F1 of (EPB X BB) X RG Disease Tolerant Red is the most productive tomato I've ever grown with over 80 pounds of fruit per plant.

The primary reason for hybrid tomatoes is to combine disease tolerances that would otherwise be very difficult to have in the same plant. We had a discussion about some work to integrate the I3 gene with SW5 which was finally done a year or so ago. Until then, linkage prevented the two genes being in the same plant except as an F1 hybrid.

The SFT work was publicized a year ago so the info presented is not really new. What is significant is that it is now shown that the bio pathway involved exists in most flowering plants. It is inferred that manipulation of the biopath can increase or decrease production for many food plants.

[Hermitian]

Originally Posted by Fusion_power

A good summary would be that hybrid tomatoes are more consistent than most open pollinated tomatoes. There are a few open pollinated varieties that outproduce almost all of the hybrids. The stabilized cross of Eva Purple Ball X Big Beef is highly productive. An F1 of (EPB X BB) X RG Disease Tolerant Red is the most productive tomato I've ever grown with over 80 pounds of fruit per plant.

The primary reason for hybrid tomatoes is to combine disease tolerances that would otherwise be very difficult to have in the same plant. We had a discussion about some work to integrate the I3 gene with SW5 which was finally done a year or so ago. Until then, linkage prevented the two genes being in the same plant except as an F1 hybrid.

The SFT work was publicized a year ago so the info presented is not really new. What is significant is that it is now shown that the bio pathway involved exists in most flowering plants. It is inferred that manipulation of the biopath can increase or decrease production for many food plants.

Great summary. Thank you.

[ChrisK]

I would be curious what level of heterosis and for what traits is seen in the large commercial operations like Syngenta and Seminis who are breeding for commercial traits for commodity size growers. This kind of info is not likely to be shared though.

Who is the "we" that discussed the I3 and SW5 breeding and what was the context?

Originally Posted by Fusion_power

A good summary would be that hybrid tomatoes are more consistent than most open pollinated tomatoes. There are a few open pollinated varieties that outproduce almost all of the hybrids. The stabilized cross of Eva Purple Ball X Big Beef is highly productive. An F1 of (EPB X BB) X RG Disease Tolerant Red is the most productive tomato I've ever grown with over 80 pounds of fruit per plant.

The primary reason for hybrid tomatoes is to combine disease tolerances that would otherwise be very difficult to have in the same plant. We had a discussion about some work to integrate the I3 gene with SW5 which was finally done a year or so ago. Until then, linkage prevented the two genes being in the same plant except as an F1 hybrid.

The SFT work was publicized a year ago so the info presented is not really new. What is significant is that it is now shown that the bio pathway involved exists in most flowering plants. It is inferred that manipulation of the biopath can increase or decrease production for many food plants.

[Fusion_power]

I had to dig around a bit. Memory slipped, it was sw5 and ph3, not I3. David Francis did the work and has applied for a patent for the line with the genes combined. Search for "Francis ph3 sw5 tomato" and you will find a few relevant documents.

Here is another significant document that indicates a possible use for LA0417.

http://vegetablemdonline.ppath.corne...s_TDW_2011.pdf

[ChrisK]

Didn't show resistance in the field though. And, it had the highest disease rating.

Originally Posted by Fusion_power

Here is another significant document that indicates a possible use for LA0417.

[Fusion_power]

LA0417 is an aggregated population. In my garden, only 1 plant out of 8 showed resistance and it was to septoria, not bacterial spot.

http://tgrc.ucdavis.edu/Data/Acc/Acc...contains=false

The description shows this line is a homogenized population of seed sampled from 31 plants. I suspect but cannot prove yet that the 1 plant in 8 in my garden was what David Francis ran into. He evaluated one or more tolerant plants in the greenhouse, then had susceptible plants in the field trial. But regardless of this, the fact that one plant from this line was exceptional in my garden and the same line showed bacterial spot tolerance in a greenhouse is very interesting. Also, there are 5 different strains of Xanthamonas that cause Bacterial Spot. It is possible they were innoculating with one strain in the greenhouse and another affected the plants in the field. While this would be less useful than broad spectrum tolerance to bacterial spot, it would still be a useful gene combination to stack into a tomato variety.

My suspicion is that there is one or more genes in LA0417 that provide moderate levels of resistance to both bacterial and fungal pathogens. These genes have small but incremental effects that could be stacked into a cultivated tomato. I think David Francis missed this potential.

[ChrisK]

From the Plant Cell, a top tier journal in my field.

Heterosis

[bower]

Thank you Chris. Lots of food for thought there...

The SFT paper does give a pretty straightforward description of plants with the SFT allele that results in yield heterosis: few, large fruit.

This is really ironic to me, since varieties that meet that description have always made me downright sad, even when the fruit are fantastic, because of the space limitations I have to live with.

Nothing is stranger than genetics, afaict.

[brokenbar]

I just finished reading the 20 book series "Aubrey & Maturin" Which is the series that "Master & Commander" was based on. (This is my year for everything I can read about the Napoleonic Wars...)

This is an outstanding series that "fleshes out" the Master & Commander characters. If you are a history/nautical or weapons buff, this series gives much detail and it covers a 20 year period.

Maturin is a Physician-Surgeon who moonlights as a naturalist/botanist. The series follows his constant search for unidentified species. In the natural course of the sailings of a British Man Of War, Maturin is priviledged to visit many ports of call and heretofore unexplored islands and distant coasts (At the pleasure of Jack Aubrey and the constraints of war.) The reader is there when new species are named and identified and it was a real pleasure to learn about so many different species in an entertaining read.

Aubrey is much like the Russel Crowe character: many different faces, moods, opinions and prejudices all lumped together and constantly tested by his very different style of leadership (for that period in history) along with his constant passion for promotion and the trials of dealing with the British Naval Heirarchy and their sometimes absurd and haphazard methods of fighting a war. Jack Aubrey is a pistol!

This was a great read and educational as well as entertaining. My husband found them all on line and sent the files to Amazon who converted them for my Kindle so they cost me nothing!


Highly recommended!

[ChrisK]

I ran across another FT paper today that showed overexpression of citrus FT (CsFT) in combination with down-regulating β-carotene hydroxylase gave up to 36 fold higher β-carotene content in the orange fruits on plants that produced in a short time frame. Unfortunately, it's behind a pay wall and I cant post it here.

Here is another one from Fig.

Expression of FcFT1, a FLOWERING LOCUS T-like gene, is regulated by light and associated with inflorescence differentiation in fig (Ficus carica L.)

The FT story is not really new. Lots of folks have been working on it for quite a while.

Originally Posted by bower

Thank you Chris. Lots of food for thought there...

The SFT paper does give a pretty straightforward description of plants with the SFT allele that results in yield heterosis: few, large fruit.

This is really ironic to me, since varieties that meet that description have always made me downright sad, even when the fruit are fantastic, because of the space limitations I have to live with.

Nothing is stranger than genetics, afaict.

[ChrisK]

The science has moved past the political debates. Plant Biotechnology Journal has an open access review issue dedicated to metabolic engineering. From early 2013:

Special Issue: Metabolic Engineering

[ChrisK]

Perhaps these posts would be better placed in the "what are you reading thread" and not the scientific papers thread. Just a thought.

Originally Posted by brokenbar

I just finished reading the 20 book series "Aubrey & Maturin" snip

[ChrisK]

A masters thesis on the genetics of grafting success. (Haven't read it yet)

Abstract
Grafting is a technique that has been used for fruit trees and vine crops for thousand years. Grafting to rootstocks is becoming popular in annual vegetable production to control soil-borne diseases, replace fumigation, increase yield, increase tolerance to abiotic stress, and impart vigor. Previous research indicates that inconsistent seed quality and lack of information about rootstock-scion compatibility affect the efficiency of grafting, raises cost, and inhibits adoption of the technology. The goals of this research were to address limitations in seed quality and graft efficiency. The specific objectives were: a) evaluate genetic and environmental factors affecting quality of seed in hybrids derived from interspecific crosses, b) improve grafting success through use of adhesives, and c) determine the genetic basis of graft failure between rootstock and scion. Tomato is a model for grafting annual vegetables due to the importance of the crop and the extensive genetic resources available. To assess the potential to select for improved seed quality, experimental rootstocks were developed through pollination of cultivated (Solanum lycopersicum L.) parental lines as female parents and 11 accessions of wild species as male parents. Seed quality was evaluated based on seed size (weight) and total germinability for each hybrid produced. Maternal effects and environment determined fruit set. Specific genotype combinations and environment determined seed yield. Seed size was mainly affected by genetic components, while seed germination was affected by
both genetics and environmental factors. Seed size can be used as selection criterion in breeding program for early selection of rootstock seed quality. To improve graft success, nine different tomato rootstocks were grafted using the traditional tube method of grafting and using adhesives. Despite wide variation across rootstock genotypes and grafting environment, grafting using adhesives resulted in higher grafting success. To determine the genetic basis of graft failure, molecular markers were exploited for quantitative trait locus (QTL) analysis. An advanced backcross population (BC3S4), derived from two S. lycopersicum parents (H7998 × OH881199), was evaluated for graft failure, using 10 plants from each family as rootstocks with the entire experiment repeated twice. The genotyping of the BC3S4 population was conducted with 78 polymorphic markers for the marker-trait analysis. A second population was developed as an F2 (H7998 × Ohio MR13) and evaluated for survival and scion height as a validation of the marker-trait associations. We identified potential regions of the genome affecting grafting failure or success on chromosome 9, and two QTL for scion height on chromosome 2 and 4. We were not able to validate these putative QTL due to the lack of overlapping markers across the two populations. The findings of this thesis work indicated that wide crosses could produce rootstocks with high seed quality. I identified key selection points in the breeding of new tomato rootstocks. At the same time, I demonstrated that control of the seed production environment is essential to obtain high quality seed from wide-cross hybrids. I also demonstrated that grafting success can be increased using adhesives in the process, and grafting failure appears to have a genetic basis, with failure associated with alleles from H7998

[brokenbar]

Originally Posted by ChrisK

Perhaps these posts would be better placed in the "what are you reading thread" and not the scientific papers thread. Just a thought.

Isn't the title of this thread "Winter Reading"? I was unaware that it was a "Scientific Papers" thread. Perhaps the title of the thread is misleading? I confess I did not slog my way through the scientific posts but rather, glanced at the thread title and posted accordingly. Please feel free to have my post removed.