QTL Mapping of Winter Hardiness Genes in Lentil

chickpea (Cicer arietinum L.) is reportedly controlled by at least five genes with tolerance dominant over Lentil (Lens culinaris Medik.) germplasm with sufficient winter susceptibility (Malhotra and Singh, 1990). hardiness to survive most winters in cold northern areas is available. However, the use of that germplasm in breeding programs is hampered One of the major problems in characterizing the geby variable winter conditions that make field evaluations needed for netic control of winter hardiness is inconsistency of field effective breeding and selection difficult. Our objectives were to gain and freezing tests. Assessing winter hardiness in the additional information on the genetics of winter hardiness in lentil field can be affected by numerous environmental factors by QTL analysis and to identify markers for use in marker-assisted including cold temperatures, freeze-thaw cycles, water selection. A total of 106 F6 derived recombinant inbred lines (RILs) logging, ice encasement, and diseases (Dexter, 1956; from the cross WA8649090/Precoz were evaluated for winter survival Lewitt, 1980; Blum, 1988). The complexity of winter in the field at Pullman, WA, USA, Haymana, Turkey, and Sivas, hardiness is dependent on developmentally regulated Turkey, in a randomized complete block design with three replications processes such as the ability to acclimate to low and over 3 yr. Winter survival was based on plant stand counts before and after winter. In addition, winter injury was monitored at Pullman freezing temperatures and the ability to alter physiologiduring the 1998-1999 winter season. Mean survival of the RILs was cally complex pathways (Palta et al. 1997). For example, 49.7, 5.3, and 89.5% at Haymana in 1997-1998, at Pullman in 1998in cereals the expression of winter hardiness depends on 1999, and at Haymana in 1999-2000, respectively. For QTL analysis a number of interacting factors including vernalization of winter survival, three QTL were detected at Haymana in 1997requirement, response to changing photoperiod, and 1998, one QTL was detected at Pullman in 1998-1999, and three QTL tolerance to low temperatures (Pan et al., 1994). In were identified at Haymana in 1999-2000. Only one of the QTL was legumes, it is not known whether vernalization and phocommon to all environments. For winter injury scores at Pullman in toperiod sensitivity are required for development of 1999, four QTL were identified that influenced winter survival. Overall winter hardiness. results indicated that winter hardiness is influenced by several genes and the cumulative effects of winter stress. Improving winter hardiness on a phenotypic basis is difficult because the trait is complex and strongly affected by environmental factors. Moreover, screening for winter hardiness is hampered by the existence of S to cold temperature limits the use of genotype environment interactions. DNA markers lentil as a fall-sown winter annual crop in temperate closely linked to the winter hardiness genes represent highland areas of the world. Germplasm has been identia promising selection tool. fied with good winter hardiness (Erskine et al., 1981; With molecular marker technology, it may be possible Spaeth and Muehlbauer, 1991), which makes it possible to elucidate the genetics of winter hardiness in lentil. to breed lentil cultivars that can be fall seeded. However, Genetic studies of winter hardiness using molecular the genetics of winter hardiness in lentil is not well techniques have been reported in various crops includunderstood. Identifying genetic factors that contribute ing barley (Hordeum vulgare L.) (Hayes et al., 1993; to winter survival is critical to effective breeding for Pan et al., 1994), oil seed brassica (Brassica napus L.) winter hardiness in lentil. (Teutonico et al., 1995), and alfalfa (Medicago sativa Genetic studies on winter hardiness of lentil, using recombinant inbred line populations, indicated that the L.) (Brouwer et al., 2000). Molecular marker analysis trait is controlled by several genes (Kahraman et al., of winter hardiness in wheat (Triticum aestivum L.) 2003). Winter hardiness in pea (Pisum sativum L.) is showed that different QTL controlled vernalization rereportedly controlled by dominant genes (Cousin et al., quirement and frost tolerance (Galiba et al., 1995), while 1985) and additive genes (Auld et al., 1983). Three or QTL controlling vernalization and freezing tolerance in four genes appeared to be responsible for winter hardioil seed rape were mapped to the same genomic region ness in pea (Liesenfeld et al., 1986). Cold tolerance in (Teutonico et al., 1995). Genetic linkage maps have been developed for variA. Kahraman, Harran Universitesi Ziraat Fakultesi Tarla Bitkileri ous lentil populations (Havey and Muehlbauer, 1989; Bolumu, Sanliurfa, Turkey 63040; I. Kusmenoglu, Ihracatci Birlikleri Muehlbauer et al., 1989; Tahir, 1990; Eujayl et al., 1998), Tohumculuk ve Arastirma San. Ve Tic. A.S. Ergazi Mah. Koyici but none included the genes for winter hardiness. The Serpmeleri No. 4 Batikent/Ankara, Turkey; N. Aydin, A. Aydogan, use of molecular markers to map genomic regions conAnkara Tarla Bitkileri Merkezi Arastirma Ens. Mud. PK 226 Ulus, Ankara, Turkey; W. Erskine, ICARDA, International Center for trolling winter hardiness and related traits would imAgricultural Research in the Dry Areas, P.O. Box 5466, Aleppo, prove our understanding of the genetic control of these Syria; F.J. Muehlbauer, USDA-ARS and the Department of Crop traits. A RIL population from a winter hardy nonand Soil Sciences, 303W Johnson Hall, Washington State University, Pullman, WA 99164-6434, USA. Received 15 Oct. 2002. *Corresponding author ([email protected]). Abbreviations: AFLP, amplified fragment length polymorphism; ISSR, inter simple sequence repeats; QTL, quantitative trait loci; RAPD, Published in Crop Sci. 44:13–22 (2004).  Crop Science Society of America random amplified polymorphic DNA; RIL, recombinant inbred line; WH, winter hardiness. 677 S. Segoe Rd., Madison, WI 53711 USA