Maize Pollen Availability is a Critical Factor for DH Wheat Development during Extreme Low Temperature

With the rapid increase in world population the production of wheat will play a pivotal role on food
security and the global economy. Double haploid (DH) technology is a new boon for rapid
development of new homozygous lines, which otherwise is achieved in more than seven years
through conventional breeding programmes. Limitation of getting maize pollen during low temperature
of winter in northern India is a challenge for pseudo-seeds production during wheat maize
hybridization for production of DH lines. Pollen of maize is shortly viable and storage of the same at
lower temperature and high relative humidity could increase its viability up to a week at 4°C as
proposed by earlier studies. Weather conditions greatly influence pollen shedding phenomenon. Cool,
humid temperature delays the pollen shed while hot and dry conditions favors the same. The present
study was conducted to determine the efficiency of pollen development during extreme cold under
four different conditions viz. open condition (under shade from top), in polyhouse, in tunnel (inside
polyhouse with hot air supply) and on the ground soil. The plants in tunnel showed early spike
emergence and pollen shedding in comparison to plants in natural environment like in open and on
the ground. Chlorophyll content was least in plants in tunnel and highest in the plants sowed on the
ground. Stem girth and plant height was also less in plants grown under tunnel. Conclusively, for early
availability and regular supply of pollen the maize plants should be grown under tunnel with hot air
supply.