the Symposium on Wheats for More Tropical Environments - cimmyt

61Research PrioritiesVarietal developmentResearch on high-yielding varieties ofwheat was initiated a few years before<strong>the</strong> independence of Bangladesh, butsystematic research was initiated onlyin 1971, with <strong>the</strong> scheme entitled <strong>the</strong>Accelerated Wheat Research Program.This program was based on <strong>the</strong>development of germplasm and ofpersonnel; CIMMYT provided help inboth areas. Initially, promising varietiesselected from international nurserieswere recommended for commercialcultivation and, simultaneously,agronomic requirements of <strong>the</strong> varietiesand seed storage practices were madeavailable to <strong>the</strong> growers.Varieties now under cultivation includeSonalika (60 to 70%), followed byINIA 66 (10 to 15%); o<strong>the</strong>rs grown areTanori 71, Jupateco 73 and Pavon 76.The farmers' preference for Sonalika isdue to its short maturity period (100 to105 days), attractive large white grainand wide adaptation under bothirrigated and dryland conditions; it isespecially suitable for late seeding.However, Sonalika is now susceptible toleaf rust and leaf blotch diseases.Balaka, a white-grained variety,recommended in 1979 for late seedingunder dryland and partially irrigatedconditions, is now in cultivation (1983­84 season). Four new varieties, Ananda,Kanchan, Akbar and Barkat. werereleased in 1983 and are in a seedmultiplicationprogram. They areresistant to leaf rust and moderatelyresistant to o<strong>the</strong>r foliar diseases andhave a 10 to 20% yield advantage overSonalika. It is hoped that <strong>the</strong>se varietieswill soon replace Sonalika.The breeding materials from nationaland international programs are beingevaluated. The superior genotypesselected from international sources areentered into <strong>the</strong> national program. Atpresent, about 400 single and topcrosses are made annually. Individualplant selections are also made underBangladesh conditions from <strong>the</strong>segregating F2 spring x winter andspring x spring crosses, including <strong>the</strong>F2 helminthosporium nursery materialreceived from CIMMYT.Since <strong>the</strong> majority of <strong>the</strong> wheat area israinfed, tolerance to drought andresistance to leaf rust and o<strong>the</strong>r foliardiseases, especially leaf blotch causedby H. sattvum, is of primaryimportance. Emphasis is being placedon <strong>the</strong> follOWing areas:• Evolve short-duration varieties,similar to Sonalika in maturity, withpost-an<strong>the</strong>sis tolerance to heat andsuitable for late plantings after <strong>the</strong>harvest of transplanted amon rice;• Develop varieties with high yieldpotential for optimum seeding dates(mid to late November), suitable fordryland and irrigated situations;• Evolve juvenile heat-tolerantvarieties suitable for late October orearly November planting, especiallyfor improved tillering ability underhigh temperatures;• Develop varieties suitable forsemisaline soils, which are found invast areas and are lying idle in <strong>the</strong>sou<strong>the</strong>astern and southwestern partsof <strong>the</strong> country;• Develop varieties tolerant to <strong>the</strong> lowpH of some areas, and• Develop durum wheat varietieswhich can improve <strong>the</strong> quality offoods. such as sUji, semolina andnoodles, which are now beingprepared from bread wheats.