Performance of some elite potato cultivars under abiotic stress at North Sinai.

The current experiment was adopted during the summer 2018, fall 2018/2019 and summer 2019 respectively at the Experimental Farm of Baloza station, Desert Research Center. North Sinai Governorate, Egypt to study the effect of different doses of irradiation (0, 20, 30 and 40 Gy), three irrigation levels (100, 80 and 60% field capacity on growth, yield and its quality of some potato cultivars (Spunta, Cara, Caruso and Hermes). Treated Spunta cultivar pre planting with 20 (Gy) and irrigated with 80% field capacity was the best treatment for increasing number of aerial stem/plants, leaf area, total chlorophyll in leaves, average tuber weight, and total yield/fed. Hermes cultivar with 20 (Gy) and irrigation level of 80% was the best for increasing dry matter content in tuber in both mutagenic generations.

Stability and anatomical parameters of irradiated potato cultivars under drought stress.

This study was carried out in Desert Research Center and Faculty of Agriculture, Zagazig University, Egypt, under North Sinai conditions during three growing seasons, i.e., summer 2018, fall 2018/2019 and summer 2019 to assess the effect of radiation mutants on leaf histological features and genetic stability of the productivity of some potato cultivars under drought stress conditions. Results reveal that the genotypes can be statistically classified based on regression coefficient (bi), deviation from regression (S2di) to 4 groups (with low in S2di are considered in all groups) as: (i) Genotype with elevated average, bi = 1, it is considered as stable genotype where Cara cultivar (both generations) was included. (ii) Genotype with elevated average, bi > 1 as genotype with average stability where spunta cultivar was involved. (iii) Genotype with low mean, bi < 1 as genotype with low stability where hermes (both primary (M1) and secondary (M2) radiated generations) and Caruso (2nd generation) cultivars were involved. (iv) Genotypes including a few bi values in one generation, as genotype including low stability but are not recommended for use in this generation where Caruso cv in M1 was included. The results indicated that 20 Gy irradiation exposure revealed that Spunta cultivar produced markedly high mean combined over yield during M1 (11.771 ton/fed) and M2 (10.97 ton/fed) generations than other genotypes and ranked first over all environments. It proves that Hermes could be employed as anti-stress genotypes under stress conditions (negative conditions or poor yielding). However, spunta followed by cara cv. represented a good performance in M2 production yield (10.97 and 8.51 ton/fed, respectively), slight drift from the regression line and coefficient close to 1, therefore, both cultivars were excellent between genotypes in shape of yield stability and is recommended for different conditions. According to anatomical studies, 80 % from field capacity (FC) decreased the thickness of medvein and lamina of potato cv. spunta, also, dimensions of medvein bundle and mean diameter of vessels. In conclusion, plants treated with gamma ray at level 20 and grown under 80 % FC induced prominent increase in all previous characters.