Heritability of Fusarium Head Blight Resistance and Deoxynivalenol Accumulation from Barley Accession CIho 4196

of the most resistant two-rowed barley accessions identified is CIho 4196 (Prom et al., 1996; Takeda, 1992). Fusarium head blight (FHB), incited by Fusarium graminearum This accession originates from China and is being used Schwabe [telomorph Gibberella zea (Schwein)], has caused devastating losses to yield and quality of barley (Hordeum vulgare L.) proextensively as a parent by the six-rowed barley breeding duced in the upper U.S. Midwest from 1993 to 2000. Design of an program at North Dakota State University (NDSU). efficient breeding strategy for developing FHB resistant cultivars is In general, CIho 4196 and most of the other resistant dependent on knowing (i) the heritability of FHB resistance and genotypes identified by Prom et al. (1996) tend to head accumulation of deoxynivalenol (DON), a mycotoxin contaminant and mature later, and are taller than cultivars currently produced by F. graminearum and (ii) the correlated response of other grown in the upper U.S. Midwest. traits during selection for reduced FHB. We conducted field studies To design an efficient breeding strategy for developin FHB disease nurseries using F4:5 and F4:6 families from the cross ing FHB resistant cultivars, we need to know several between the FHB susceptible six-rowed cultivar Foster and the resisthings about the accessions used as parents; particularly tant two-rowed accession CIho 4196 to gain knowledge in the areas we need to know the heritability of FHB resistance and listed above. Heritability of FHB severity and DON accumulation was 0.65 and 0.46, respectively. A moderately strong positive association DON accumulation. Information on the heritability of between FHB severity and DON accumulation was observed (r FHB resistance and DON accumulation in barley is 0.62). FHB severity and DON accumulation were negatively associlimited. Takeda (1990) studied the genetic behavior of ated with plant height, days to heading, spike angle, and spike density. FHB resistance in five crosses between two-rowed and The selection differentials calculated between the top F4:6 families six-rowed barley in the F2, F3, and F4 generations. He selected for low FHB severity and the unselected F4:5 families were suggested that resistance to FHB is under the control moderately high for FHB severity, DON accumulation, and days to of quantitative genes. Heritability estimated from the heading. Less than 14% of the selected lines had six-rowed spikes. genetic gain:selection differential ratio was 0.25 in the No difference in plant height was observed between the selected and F2–F3 selection response and 0.33 in the F3–F4. Takeda unselected families. Thus, development of FHB resistant lines with (1992) reported that heritability for FHB resistance in acceptable DON accumulation and days to heading is obtainable. However, because no lines were as short as Foster, development of barley was 0.6 in the broad sense and 0.4 in the narrow FHB resistant plants with acceptable plant height from a cross using sense, and that resistance was under the control of preCIho 4196 as a parent will be difficult. dominantly additive genes. Development of a suitable breeding strategy is also dependent on knowing the correlated responses of seN dakota is the leading state in barley produclecting for reduced FHB severity on DON accumulation with 30.6% of the overall U.S. production tion, days to heading, and plant height. Limited infor(USDA, 2000). The area sown and harvested has been mation is available on this topic for these traits. The significantly reduced in the last few years because in objectives of this study were (i) to estimate the heritabilpart of FHB. Since 1993, barley losses due to FHB in ity of FHB resistance and DON accumulation and (ii) the upper U.S. Midwest have exceeded $200 million to evaluate the selection for reduced FHB severity at (U.S. GAO, 1999). Some of the losses due to FHB are an intensity of 40% and to determine the correlated attributed to accumulation of DON, a mycotoxin conresponses on DON accumulation, days to heading, and taminant of cereals produced by F. graminearum. Barley plant height in a population derived from the cross Foscontaining DON accumulations greater than 0.6 g g 1 ter/CIho 4196. may be rejected by the malting and brewing industries because of marketing and processing concerns. MATERIALS AND METHODS Tillage, crop rotation, and chemical control have been suggested as methods for reducing FHB severity; yet, Plant Materials success with these methods has been limited. Genetic One spike was harvested from 250 individual F2 plants from resistance offers the greatest potential for reducing the cross Foster/CIho 4196 grown at Fargo, ND, during sumFHB. Nearly 40 barley genotypes have been identified mer 1996. Two cycles of generation advancement were done with partial resistance to FHB (Prom et al., 1996). One in the greenhouse during the fall of 1996 and the spring of 1997. In each cycle, seed from one plant of each line was harvested and advanced to the next generation. Finally, three C.A. Urrea, CIMMYT, Mexico; R.D. Horsley, Dep. of Plant Sciences, plants per line grown in the spring 1997 greenhouse were North Dakota State Univ., Fargo, ND 58105-5051; B.J. Steffenson, selfed and harvested in bulk to generate the F4:5 generation. Dep. of Plant Pathology, 495 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108; P.B. Schwarz, Dep. of Cereal and Food Sciences, North Dakota State Univ., Fargo, ND 58105. Received 15 July 2001. Field Experiments *Corresponding author ([email protected]. One hundred fifty of the 250 F4:5 recombinant inbred lines were randomly selected and sown at Langdon, ND, on 17 May Published in Crop Sci. 42:1404–1408 (2002). 1404 Published September, 2002