Morphological traits and resistance to Egyptian broomrape weed (Orobanche aegyptiaca Pers.) in tobacco under greenhouse condition

Abstract

Broomrape (Orobanche aegyptiaca Pers.) is a debilitating holoparasiting weed in tobacco (Nicotiana tabacum L.) fields with devastating effects on its production. In this study, the reaction of 26 tobacco genotypes was evaluated against broomrape weed in randomized complete block design with three replications under greenhouse condition. Tobacco genotypes were planted in both non-inoculated and inoculated conditions where the soil of inoculated pots was mixed with 0.06 g of broomrape seed. The genotype by trait (GT) biplot explained 66% of the total variation of the standardized data and the polygon view of GT presented for 11 traits showed 5 vertex genotypes. Genotype G20 was the best in terms of leaf properties (length, width, number and area), and stem girth while G14 was the best genotype against broomrapes number as well as fresh and dry weight of broomrapes. Genotype G4 was identified for good performance in plant height and fresh weight total while G19 and G26 were best genotypes in terms of total fresh weight. Based on vector view biplot, a strong positive association among leaf properties, number of broomrapes, fresh and dry weight of broomrapes, and among plant height, fresh weight and dry weight of leaf yield were detected. According to ideal genotype biplot, genotype G20 followed by G3, G13 and G24 were the most favourable genotypes regarding all of the measured traits. The plant height, leaf number per plant and stem girth could be considered as effective selection criteria evolving high yielding genotypes. Finally, genotypes G26 and G19 are good candidates for improving most of the measured traits and for obtaining resistance to the Egyptian broomrape.