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(Hawtin and Singh 1983). Asv.-,hyta blight can also limit productivity in Pakistan,
India, Ethiopia and Southern Europe. There are many ways of reducing the
severity of the disease, such as rotation and the application of seed dressings and
ft,;gicides, but resistant cultivars would offer by far the most effective means of
control.
The first resistant desi cultivar, namely, F8, was released 40 years ago in India
(Luthra et al. 1941). This was followed by the release of C 12-34 in 1949 (Ahmed
et al. 1949) and C 727 in 1962 (Aziz 1962) for Pakistan, and C 235 in 1962 (Bedi
and Athwal 1962) for India. However, these cultivars soon became susceptible,
owing to the occurrence of new races of ascochyta blight (Grewal and Vir 1974),
and after 1962 there has been no report of release of a resistant desi cultivar. To
the best knowledge of the authors, no resistant kabuli cultivar has ever been
released for commercial production in "VAVst Asia and North Africa. As a result,
only susceptible cultivars or landraces
are being cultivated in an area in which
ascochyta blight is endemic, restilting in instability of production.
. Recently Kauser (1976) and Retig and Lehrer (1977) have reemphasized the
need for the development of blight-resistant cultivars, and Haq et al. (1981) have
advocated the use of mutation breeding. Several limitations such as the absence
of stable sources of resistance and of effective screening techniques, combined
with inability to identify physiologic races and ignorance of the genetic control of
resistance, have in the past inhibited plant breeders from launching aggressive
breeding programs. Singh el al. (1983) have reported several sources of resistance
and an effective screening technique, and some information is available on
the inheritance of resistance. The time thus seems ripe to attempt solving the
blight disease problem through resistance breeding.
In this paper the progress made at ICARDA through the development of
blight-resistant cultivars, and the future breeding strategies for developing genet­
ic material for the endemic areas of the world are discussed.
Genetics of Resistance
Review of Past Work
In 1953, Hafiz and Ashraf reported that the resistance to ascochyta blight was
determined by a single dominant gene in two parents, namely, F8 and FIO. Later
Vir et al. (1975) and Eser (1976) reported a similar finding. Recently Singh and
Reddy (1983) have reported that a single dominant gene conditioned resistance
in four parents, ILC 72, ILC 183, ILC 200 and ICC 4935, whereas the resistance
in ILC 191 was conferred by a single recessive gene. This was the first report on
identification of a recessive gene governing resistance to blight. A summary of
current information on inheritance of resistance is given in Tab. 1.
Now that a number of resistant sources have been identified at Tel Hadya and