Marker-Assisted Backcrossing Selection for High O/L Ratio in Cultivated Peanut - Translational Genomics for Crop Breeding: Abiotic Stress, Yield and Quality - page 177

Chapter 11

Marker-Assisted Backcrossing Selection
for High O/L Ratio in Cultivated Peanut

PadmalathaKoilkonda,ChikaraKuwata,MasanobuFukami,KentaShirasawa,
KohAoki,SatoshiTabata,MakotoHasegawa,HiroyukiKiyoshima,
ShigeruSuzuki,ShigemiSasamoto,AtsushiKurabayashi,HisanoTsuruoka,
TsuyukoWada,andSachikoIsobe

Abstract

Peanut ( Arachis hypogaea L.) is an important food legume and oilseed crop cultivated worldwide.
The quality of peanut oil depends on the properties of the oil, one of which is the oleic/linoleic acid
ratio (O/L ratio). The two genes related to the O/L ratio, ahFAD2A and ahFAD2B , were previously
identified in peanut. In this chapter, marker-assisted backcrossing selection (MABS) for high O/L
ratio in peanut is demonstrated with a breeding line showing a high O/L ratio ('YI-0311') and an elite
line with medium O/L ratio ('Nakateyutaka') as donor and backcross parents, respectively.
A total of 204 F 2 plants were obtained from 34 F 1 plants. Seven F 2 lines exhibited a high O/L ratio
and had homozygous 'YI-0311' genotypes on the two FA D 2 loci. Four F 3 seeds were generated from
each of the three F 2 plants, and a total of 108 BC 1 F 1 seeds were developed from the 12 F 3 plants.
Twelve of the 108 BC 1 F 1 plants were selected according to the genotypes of 42 genome-wide (GW)
DNA markers. A total of 178 BC 1 F 2 plants were developed from the 12 BC 1 F 1 plants, and 16 of
the 178 showed a homozygous 'YI-0311' genotype on the FA D 2 loci. Of the 16 BC 1 F 2 plants, eight
were selected based on the genotypes of the 19 GW markers, and then backcrossed. A total of 26
BC 2 F 1 plants were developed, and 10 BC 2 F 1 plants were selected according to GW genotypes. Of
the subsequently developed 205 BC 2 F 2 plants, nine showed homozygous 'YI-0311' genotypes on the
FAD2 loci. At present (January 2012), BC Cycle 3 is in process. In addition to low cost for selection
of high O/L ratio plants, the higher homozygous backcrossing ratio suggested efficiency of MABS
for high O/L ratio breeding in cultivated peanut.

wide in temperate and tropical zones. It cov-
ers 23 million hectares, which produce about
50 million metric tons, with an average yield
1.6 tons/ha (FAOSTAT 2010). Cultivated peanuts

Introduction

Peanut ( Arachis hypogaea L.) is an important
food legume and oilseed crop cultivated world-