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plant breeding (CPB) has been successful for farmers in high potential environ-
ments. However, it did not make good progress in marginal environments because
such environments are highly diverse and farmers are generally poor, hence they
cannot afford expensive inputs including certified seed (Morris and Bellon 2004 ;
Ceccarelli and Grando 2007 ). In CPB, initial selection in large populations of breed-
ing materials is conducted on optimally managed research stations by breeders.
PVS has been reported as an efficient approach for disseminating new improved
varieties (Ortiz-Ferrara et al. 2001 ; Thapa et al. 2009 ). It is capable of better address-
ing farmers’ needs of new varieties that very often are not recognized using conven-
tional non-participatory varietal development approach. PVS could complement
ongoing varietal development efforts in the region to help farmers by providing
them with a wider option of germplasm to evaluate and adopt under their own con-
ditions (Witcombe et al. 2003 ). PVS was successfully used in maize in Africa
(Snapp 1999 ; De Groote et al. 2002 ) and has proven to be an efficient approach to
developing and disseminating new varieties through close collaboration with farm-
ers in South Asia as well (Ortiz-Ferrara et al. 2007 ).
8.4 Indirect Selection Approaches
The genetic diversity of many crops has greatly reduced with the introduction of
improved varieties. The choice for selection in modern germplasm is somehow lim-
ited now. The diversity of germplasm has a significant impact on the improvement
of crop plants. Narrow genetic diversity is a bottleneck in breeding; it is necessary
to incorporate more genetically diverse germplasm in the breeding program in order
to broaden the gene pools of various crops. Genetic variation among parental lines
is necessary to derive superior progeny for crossing and selection. However, crosses
are often performed among elite genotypes having similar agronomic traits.
The main goal of most plant scientists is to improve/increase yield. Breeding
programs are usually started with the intention of improving some genotype/culti-
var etc. Depending on the objective, various approaches are taken while starting the
breeding program. The improvement may be thought identifying genotypes tolerant
to biotic and abiotic stresses or increase in yield per se. Traditionally conventional
breeding approaches are taken which are somehow straightforward, however to
accelerate the breeding progress advantage of some technologies needs to be taken.
Studies comparing the chlorophyll fluorescence with the conventional tech-
niques indicated that chlorophyll fluorescence can be a useful tool for screening
biotic and abiotic stress tolerance in various crops (Matous et al. 2006 ). Thakur
( 2004 ) screened fruit crops for drought tolerance based on indices, namely xylem
water potential, relative water content, chlorophyll stability index, drought injury
index, and rapid test for drought tolerance. According to Chen et al. ( 2007 ), only the
chlorophyll fluorescence method has often been the most attractive tool for rapid
Q. Sohail et al.