Biology Reference
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13.1 h. Two QTLs for PP were located at the same genetic positions as QTLs
associated with GDD to flowering in LGs A and B, respectively.
Mokrani et al. (2002) identified QTLs for STF using 118 F 3 families derived
from a cross between L1 (restorer) and L2 (maintainer) lines from Syngenta
seed company sunflower collection ( Table 5-1 ). Using a genetic map
constructed with 215 AFLP and 61 SSR markers, two QTLs located on LG 9
( stf-9-1 ) and LG 10 ( stf-10-1 ) with LOD scores of 3.6 and 4.3, respectively
were detected for STF. The phenotypic variation explained by these QTLs
was 2.6% for stf-9-1 and 70.9% for stf-10-1 , respectively, and L1 parent
contributed to the favorable alleles for both the QTLs.
Bert et al. (2003) also identified the genomic regions involved in STF in
a F 2 :F 3 mapping population derived from a cross between two inbred lines
developed by INRA-France (XRQ×PSC8) in two years 1997 and 1999 ( Table
5-1 ). Five and six QTLs were detected in 1997 and 1999, respectively on
different LGs among which, four were common across the two years and
three (one on LG 7 in 1997 and two on LG 6 and LG 18 in 1999) were specific
to the year of study. The total phenotypic variance explained by five QTLs in
1997 and six QTLs in 1999 was 64.1% and 74.9%, respectively, and both
parental lines contributed equally to favorable alleles. The QTLs identified
by Bert et al. (2003) for STF were not in the same position as those reported
for the same trait by Mestries et al. (1998) on LG 9 and LG 10.
Rachid Al-Chaarani et al. (2004) identified three QTLs controlling STF
in a recombinant inbred line (RIL) mapping population derived from the
PAC2×RHA266 cross on LGs 4, 9 and 14 with LOD score of 7.5, 9.8 and
10.4, respectively with a sum of the individual phenotypic variation (R 2 ) of
52% ( Table 5-1 ) . RHA266 contributed the positive alleles for two of the three
QTLs and PAC2 contributed to only one of them. In any QTL analysis for
any quantitative or qualitative trait, it is important to compare the position
of QTLs obtained with different mapping populations and also across
various environmental conditions. Unfortunately, the comparison of the
location of QTLs is not always possible as different marker systems and
linkage group nomenclature are used for map construction and QTL
detection in different studies.
Recently, QTLs for many agronomical, physiological and developmental
traits have been detected under different water treatments in the greenhouse
and field conditions using a saturated public AFLP/SSR map of RILs from
the cross PAC2×RHA266 with standard linkage group nomenclature
(Poormohammad Kiani et al. 2007a, b, 2008, 2009). The results of these
research works are presented in 5.2.7.
5.2.1.2 Agro-morphological Traits
Morphological traits are also important in sunflower breeding. Although
some of the morphological traits, such as plant height, are not essential
 
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