How fast can a cross stabilize?

sprtsguy76 · August 19, 2011

Long story short I crossed an orange PL with a pink RL. Out of this cross in f2 generation I found a wonerful tasting orange RL. I'm now in the f3 grow out this season. All 40 seeds I sprouted were RL and even though I only grew four of them out this season they are all orange RL with very similar fruit shape. The only real noticable difference between them now is taste. Could I be close hear?!!!

Damon

Fred Hempel · August 19, 2011

Stabilization occurs every generation, as with each generation half of the gene pairs become homozygous:

F1 = hybrid generation
F2 = 50% of gene pairs homozygous
F3 = 75% of gene pairs homozygous
F4 = 87.5% of gene pairs homozygous
F5 = 93.625% of gene pairs homozygous
F6 = over 96% of gene pairs homozygous
F7 = over 98% of gene pairs homozygous

The above is true if you are following lines selected from individual plants with each generation.

Whether or not you perceive your line as "stabilized" depends on the traits that you are looking at, and when they become homozygous. If you only looking at RL vs PL you can become "stabilized" at the F2 generation.

The number of generations required to become stabilized depends on how many traits are important to you, and also how many genes are involved in determining those traits.

After 7 generations a line is, on average, pretty well stabilized, but still segregates for a small number of traits, which may or may not be easily detected.

salix · August 19, 2011

Fred, thank you for such a clear, short and succinct explanation.

August 19, 2011	#1
sprtsguy76 Tomatovillian™ Join Date: May 2007 Location: Santa Clara CA Posts: 1,125	How fast can a cross stabilize? Long story short I crossed an orange PL with a pink RL. Out of this cross in f2 generation I found a wonerful tasting orange RL. I'm now in the f3 grow out this season. All 40 seeds I sprouted were RL and even though I only grew four of them out this season they are all orange RL with very similar fruit shape. The only real noticable difference between them now is taste. Could I be close hear?!!! Damon

August 19, 2011	#2
Fred Hempel Tomatovillian™ Join Date: Dec 2010 Location: Sunol, CA Posts: 2,723	Stabilization occurs every generation, as with each generation half of the gene pairs become homozygous: F1 = hybrid generation F2 = 50% of gene pairs homozygous F3 = 75% of gene pairs homozygous F4 = 87.5% of gene pairs homozygous F5 = 93.625% of gene pairs homozygous F6 = over 96% of gene pairs homozygous F7 = over 98% of gene pairs homozygous The above is true if you are following lines selected from individual plants with each generation. Whether or not you perceive your line as "stabilized" depends on the traits that you are looking at, and when they become homozygous. If you only looking at RL vs PL you can become "stabilized" at the F2 generation. The number of generations required to become stabilized depends on how many traits are important to you, and also how many genes are involved in determining those traits. After 7 generations a line is, on average, pretty well stabilized, but still segregates for a small number of traits, which may or may not be easily detected.

August 19, 2011	#3
salix Tomatovillian™ Join Date: Dec 2007 Location: north central B.C. Posts: 2,310	Fred, thank you for such a clear, short and succinct explanation.