GENETICS AND INCORPORATION OF GLANDULAR TRICHOMES AND POLYPHENOL OXIDASE ACTIVITY INTO AN ADVANCED SOLANUM-PHUREJA-S STENOTOMUM DIPLOID POTATO POPULATION

Preliminary data on the genetics of glandular trichomes and the feasib ility of incorporating A and B glandular trichomes and polyphenol oxid ase (PPO) activity from Solanum berthaultii Hawkes (Ber) into an advan ced S. phureja Juz. et Buk.-S stenotomum Juz. (Phu-Stn) diploid potato population are presented. A random sample of four Phu-Stn clones was intercrossed with a sample of three Ber progenies (pollen bulk per pro geny) segregating for high density of A and B glandular trichomes. Nin e F1 families [(Phu-Stn) x Ber] were evaluated over two experiments in the greenhouse for A and B trichome density (5 mm2 of abaxial surface ) and PPO activity 45 days after planting. A completely randomized des ign in an experimental hierarchical classification arrangement was use d to quantify the genetic variability and to estimate broad-sense heri tabilities (defined on an individual basis) for the attributes under s tudy. To characterize the inheritance of these attributes further and to estimate narrow-sense heritabilities, fifteen backcross (BC) famili es were evaluated in a randomized complete-block design with three rep lications and analyzed by half-sib family analysis. Phenotypic and gen otypic correlations between these attributes were also estimated. In t he F1 families, broad-sense heritabilities were 0.59 and 0.41 for dens ity of A and B trichomes, respectively. In the BC population, narrow-s ense heritabilities were 0.15 and 0.08 for A trichome density and PPO activity, respectively; expression of B trichomes was almost absent in this generation. Genotype x environment interaction was significant f or density of A trichomes and highly significant for density of B tric homes in F1 families. There was some level of positive association bet ween density of A and B trichomes and PPO activity. Additive genetic v ariance of these attributes was very low in this study; therefore, sel ection schemes based on family selection and progeny testing would be an appropriate breeding strategy for improving these traits.