Inheritance of internal tuber processing attributes among selected potato (Solanum Tuberosum L.) genotypes

Abstract

The new trends in the potato industry especially in processing require analysis of yield, tuber attributes and disease resistance in the development of new potato varieties. This study evaluated selected potato genotypes with acceptable yield and blight disease resistance for specific internal tuber processing attributes and their mode of inheritance. To asses the specific tuber processing attributes, afield trial was laid out as a 5 X 6 alpha lattice design with three replications at Kachwekano Zonal Agricultural Research and Development Institute. Results showed that dry matter content was significantly different among the genotypes (P ≤ 0.01) and ranged from 16.49% to 21.85%. The best performing genotypes for dry matter content included 395438.1 (21.85%), 395096.2 (20.99%), 395077.12 (20.97%), 395015.6 (20.87%), NAROPOT3 (20.57%), KINIGI (20.26%) and 393220.54 (20.19%). Reducing sugar levels were significantly different (P ≤ 0.001) among the genotypes and ranged from 0.4mg/g (db) to 11.3mg/g (db). The best performing genotype was 395438.1 at 0.4mg/g (db). Genotypes were significantly different (P ≤ 0.001) for total tuber yield, average weight per tuber, tuber weight per plant and number of tubers per plant. The mean total tuber yield was 31.7tha-1 with the highest yielding genotype as 392657.8 (50.4tha-1). There was a negative correlation between dry matter content and reducing sugars (P ≤ 0.05) where as a positive correlation (P ≤ 0.001) was observed between total tuber yield and average weight per tuber, tuber weight per plant (P ≤ 0.01) and between total tuber yield and number of tubers per plant. Seven genotypes exhibited the desired levels of high dry matter content (≥20%) and twenty-two genotypes exhibited desired levels of low reducing sugar content (≤ 3 mg/g). These could be exploited in variety release and improvement strategies basing on internal tuber processing attributes. Mode of inheritance for specific internal tuber processing attributes was determined eight parental genotypes with varying levels of dry matter content and reducing sugars. A half diallel mating design was used and the resulting F1 progenies and parents were evaluated for combining ability. The combining abilities of parents showed additive gene action influencing dry matter content while non-additive gene action was predominant for reducing sugars, average weight per tuber and total tuber yield. The genotypesNAROPOT3 and 395096.2 as parents presented good general combining ability effects for dry matter content and reducing sugars thus can be used to improve potato genotypes for processing tuber attributes. The results indicated potential for selection of suitable parents for breeding programs to improve potato tuber processing attributes.