Selection for drought and salinity tolerance in cool-season food legumes

The increasing demand forfwd is compelling fnnncrs to cullivntc land in unfavourablc climalic nnd cdaphic cnvimnmcnts. This applies parricularly to f w d lcgumcs which oftcn have secondary stulus lomorc pruductivc. l i ~g l~c r incomc crops such as cclrals. In addition. l iun in~~ cncronchmc~ir upon both prcductivc and niarginal ngricultural llrcas is cxsccrheting abiotic strcascs such as salinity.Thc usc of irrigation toovcrcomcdruught cffects hasoltcn Icd to salini~ation of once productive land. Examplcs abound in thc Indo-Gangclic Plain of Soutli Asia (Sharmn and Gupta. 1986), Wcst Asia (Gclburd, 1985). western USA (Backlund and Hoppes. 1984) and Australia (McWilliam. 1986). Before considering ways of allcvialing drought and salinity strcsscs, i t is ncccssary to dcfinc the magnitude, scvcrlty and nature of ll~csc problems. It is also ncccssary to realize that both gcnctic and management options are available to tacklc thcm, and carcful aascasmcllt of thcir rclativc mcrils in paniculer situstiuns ih rcquircd. I l l i s ch:~ptcr rocusca on gcnctic options, wliicli involve modifying plants to cope better with thcsc slrcssc,. Although such oplions arc lcss costly, il is important to ernphuizcthst tlicy canonly cvcrbepartialaulul~ona. lnlmunity tudrouyhtandaalinily isnolpssiblc and the crop improvc~ncnt goal ahould be u tndesl cn1i;mccnicnt of y icld potcntiul and yicld slability In defined stress cnvirannic~lts. Thcac yicld targcls !nay be well below what can be cxpcclcd for thc crop under optinlum growth conditions; funhcrmore, 111e [rails rcquircd for gcnolypcs to cope with slrcsa may inhibil lhcir yicld ptenlial in conatnim-frcc cnviro~i~ncnls (Rosicllc and Hamblin, 1981). We elaborate on thcx ideas and describe approaches wc consider appropriate for the genetic improvcmenlofdroughtandralinity resistance inchickpea(Cicc~~uricri~~umL.).fab~benn(Viriu~abu L.), lentil ( k n s eulinuris Mcdik.) and pea (Pisun! sari l~~rf i~ L.).