Mehi Lal

The Use of Bio‐Agents for Management of Potato Diseases

Potato is an important food crop in the world as well as in India. It is being affected by different pathogens, viz. fungi, bacteria, viruses and nematodes. These pathogens may cause significant yield losses of the crop, if proper protection measures have not been applied. Among potato pathogens, Phytophthora infestans, Alternaria solani, Rhizoctonia solani and Fusarium spp. are the major pathogens in the fungal group, whereas Ralstonia solanacearum, Pectobacterium spp. and Streptomyces spp. are in the bacterial group. For management of these pathogens, various methods, that is, chemical control, biological control, resistant varieties, cultural control and physical control, are applied. Resistant varieties are the best and cheapest method for managing the diseases. However resistant varieties are break down their resistant over the years and moreover against some pathogen absolute resistant are not available. Chemical management is the second best option for managing the diseases, due to continuous and irrational use of the chemicals; pathogens have developed resistance against certain class of fungicides/bactericides. Moreover, these chemicals also assist in environmental pollution and toxicity in the produce. Bio‐agents are naturally occurring living organisms, which are found in rhizosphere, phylloplane, etc. These bio‐agents help in not only managing the diseases but also increasing the crop yield. Therefore, the use of bio‐agents for biological management of potato crops is the focused research area worldwide.

Evaluation of Potato Genotypes for Foliar and Tuber Resistance against Phytophthora infestans Causing Late Blight of Potato under Subtropical Plains of India

The oomycete pathogen Phytophthora infestans (Mont.) de Bary, is still an important pathogen of the potato and tomato crops after more than one hundreds seventy years of occurrence of late blight epidemic in Ireland. The late blight is one of the most destructive diseases of potato and results in yield losses up to 95% in epidemic conditions. In India, it cause up to 10-15% yield loss of potato on over all basis (Lal et al., 2016). The yield loss caused by P. infestans, can be minimized using host resistance, chemicals, forecasting, sanitation and even disease escape (Wastie, 1991). Host resistance had always been a better option than the fungicides, since these are expensive, environmentally hazardous and pathogen International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 7 Number 03 (2018) Journal homepage: http://www.ijcmas.com

Evaluation of Interspecific Somatic Hybrids of Potato (Solanum tuberosum) and Wild S. cardiophyllum for Adaptability, Tuber Dry Matter, Keeping Quality and Late Blight Resistance

Interspecific potato somatic hybrids (here after referred as ‘cph-hybrids’) derived earlier through protoplast fusion (Solanum tuberosum + S. cardiophyllum) were used in this study. The genetic potential of cph-hybrids was assessed based on the field performance in the Indian sub-tropical conditions. In general, cph-hybrids exhibited higher plant stand, poor plant vigour and late foliage maturity as compared to the control potato var. Kufri Bahar. Yield performance of cph-hybrids was poor as compared to the control, but produced 3–6 times higher marketable tuber yield than the wild parent (S. cardiophyllum). All cph-hybrids possessed significantly higher tuber dry matter content (≥ 24%) than the parents (20.82%) and var. Kufri Bahar (18.52%), excellent keeping quality and showed high resistance to late blight. Thus, based on this study the promising cph-hybrids viz., Crd 6, Crd 10 and Crd16, can be used as parents in breeding for the improvement of important traits viz., higher tuber dry matter content, better keeping quality and high late blight resistance, along with adaptability under sub-tropical conditions.