Evaluation of maize germplasm for rust {Puccinia sorghi) resistance and cold tolerance in north westernplain zone of India

摘要

Maize (Zea mays L.) is the leading world's cereal crop in terms of both total production and productivity. Both abiotic (drought, cold/frost, salinity, water logging) and biotic stresses (diseases and pests) are the major limiting factors impacting maize productivity. In northern India, winter maize is grown in the month of October and November and in spring season it is sown in the first week of February. During winter season maize crop is exposed to cold stress in the month of January that affectsyoung plants at emergence stage. Common rust (Puccinia sorghi with authority) is another biotic stress affecting its yield. This low productivity is due to both biotic and abiotic stresses and among them cold stress and common rust are the main problemsin winter /Spring planted maize grown in Northern India. The productivity of maize is higher during rabi season because there are negligible insect pest and diseases during this season and secondly the temperature is mild during grain development stage.In Haryana we may get very good grain yield during rabi season but there is always risk of cold/frost damage as the temperature many a times reaches to freezing level. And as the temperature rises there are chances of appearance of common rust at temperature 16 to 20°C. Among the foliar diseases affecting maize, the common rust caused by Puccinia sorghi is of worldwide importance (Carmona et al. 2009). It may cause extensive yellowing and premature desiccation of maize foliage, resulting in leaf necrosis, and complete destruction of photosynthetic areas. In extreme cases, heavy rust infestations may result in stunting, incomplete ear tip fill and pustules on ear husks, reducing marketabilityand yield. Although common rust epidemics are rare, the amount and timing of common rust development largely depends on temperature variability but epidemics of this disease can cause serious losses in yield and quality of corn. The severe localized outbreaks of common rust occasionally occur when environmental conditions favour the development and spread of the disease (Wright 2007; Dey etal. 2012). For every 10 increase in common rust severity prior to harvest, yield is reduced by 2.4 - 7.0 in processing sweet corn (Shah Dillard 2006).