Agriculture Reference
In-Depth Information
3 years for oil content. The oil content among wild
Arachis
accessions
ranged from 51.4% to 62.9%, 51.4% to 62.8%, and 54.2% to 63.3% in
2008, 2009, and 2010, respectively, with an
Arachis rigonii
accession
showing the highest oil contents (62.9%, 62.8%, and 61.1%), which
shows that crop wild relatives could be useful sources of variation for
introgression breeding to develop peanut cultivars with high oil content.
2. Oil Quality.
Palmitic, oleic (O), and linoleic (L) fatty acids together
constitute
90%of the total fat in peanut. Oleic acid has been associated
with increased shelf life of the products and imparts health bene
∼
ts,
whereas linoleic acid is associated with developing off-
avors during
storage due to oxidation. A germplasm line with high O/L ratio has a
longer shelf life than those with lowO/L ratios (Gorbet and Knauft 1997).
Norden et al. (1987) were the
first to report exceptionally wider ranges in
oleic (35
43%) fatty acids among peanut geno-
types in the Florida breeding program. Two closely related breeding
lines (F435-2-1 and F435-2-2) had 80% oleic and 3% linoleic fatty acid.
However, these experimental lines are not in the public domain due to
intellectual property rights (U.S. patent Nos. 5,922,390; 6,063,984;
6,121,472). Further search for germplasm with high oleate content
did not result in
-
80%) and linoleic (2
-
finding such unique accessions in large peanut germ-
plasm collections. For example, the O/L ratio in the U.S. peanut mini
core accessions ranged from 1.07 to 3.47 (Dean et al. 2009), whereas
in the ICRISAT peanut mini core the O/L ratio ranged from 0.85 to
6.91 (Upadhyaya et al. 2012a). PI 274193, PI 290594, and PI 468271 in
the U.S. peanut core had average O/L ratios of 3.1
3.5, whereas nine
accessions in the ICRISAT peanut mini core had O/L ratios from 3.0 to
6.9, with ICG 2381 having the highest O/L ratio. In both studies,
subspecies
fastigiata
accessions had lower O/L ratios than subspecies
hypogaea
accessions. A few
fastigiata
-type accessions such as ICG 6022,
ICG 12625, and ICG 1274 had O/L ratios of 3.0 (Upadhyaya et al. 2012a).
-
B. Tocopherol
Tocopherol is the major form of vitamin E and it plays an important role
in maintaining human health (Traber and Sies 1996; Bramley et al.
2000). Oilseeds are the major source of vitamin E in human diets (Hunter
and Cahoon 2007). The four forms of tocopherols (
) vary in
the number and position of methyl groups on the chromanol ring. Alpha
tocopherol is of the greatest nutritional value for humans and livestock
(DellaPenna 2005). Isleib et al. (2008) were the
α
,
β
,
γ
, and
δ
rst to report moderate
genetic variation (19
-
42%) in
α
-,
β
-,
γ
-, and
δ
-tocopherols and total
