Development of a Mo el for Marker - Assisted Selection of Specific Gravity in iploid Potato across Environments

Dry mal1er content in potato (Sownum ruberosum L.) ls an Im­ portant factor in processing llIId is ~imatl,d by specific gravlty. We perfonned quantitative tfBit loci (QTL) analysis for this trait in lx potato in three environments, A population of 110 IndJviduals WItS derived from the croSiS of It hybrid ot haploid S. ruberosum (lx) lUld S. ch4coense Bitter, with II S. phureja Juz. & Bull. clone. This pol"lla­ tion WItS characterized for 10 LWlyme loci, 44 restriction f'l:1l.gment length polymorphisms (RFLPs), and 6J random amplified poJymorphJc DNA (RAPDs). Field trials weft conducted in two tocatiO llJld effects of QTLs detected varied across envirownents. The locus with blgbest If value per QTL In eacb environment was cbosen to develop multllocus models, which explained 39 to 45% of the phenotypic vanlltioo for specilk gravity. Eacb model was also tested with data from the other environments, and In general, the predlctlve value across envlrownents was weaker. A model based on average specific gravity across environ­ ments explained a consistent proportioo of the phenotypic variation for specilk gravity wben tested across enviroo.ments. Using muJtiple environment data to develop models may be mort valUllble for [JUIJ'k.er­ assisted selection in a potato breeding program than models ba..Oled on