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In maize, hybrid vigour is exploited by
A
crossing of two inbred parental lines
B
harvesting seeds from the most productive plants
C
inducing mutations
D
bombarding the seeds with DNA
Detailed Solution
Hybrid vigour, also called heterosis, is the superiority of the hybrid over both its parents in characters such as size, growth rate, yield and resistance.
Maize is a cross-pollinated crop. Repeated self-pollination (inbreeding) is first used to produce pure inbred lines, which are homozygous but show reduced vigour (inbreeding depression).
When two different inbred parental lines are crossed, the F1 hybrid is highly heterozygous and shows marked hybrid vigour, with a much higher yield.
Hybrid maize seed is produced commercially in this way (single cross and double cross hybrids).
The vigour declines in later generations because of segregation, so fresh hybrid seed has to be produced every year; in vegetatively propagated crops it can be maintained.
Selecting the most productive plants, inducing mutations and DNA bombardment are different techniques and do not exploit hybrid vigour.
So in maize hybrid vigour is exploited by crossing two inbred parental lines.
Maize is a cross-pollinated crop. Repeated self-pollination (inbreeding) is first used to produce pure inbred lines, which are homozygous but show reduced vigour (inbreeding depression).
When two different inbred parental lines are crossed, the F1 hybrid is highly heterozygous and shows marked hybrid vigour, with a much higher yield.
Hybrid maize seed is produced commercially in this way (single cross and double cross hybrids).
The vigour declines in later generations because of segregation, so fresh hybrid seed has to be produced every year; in vegetatively propagated crops it can be maintained.
Selecting the most productive plants, inducing mutations and DNA bombardment are different techniques and do not exploit hybrid vigour.
So in maize hybrid vigour is exploited by crossing two inbred parental lines.