Growth duration and high yield do not match always. For example, if you grow deep water rice it requires about six months but yield is about 2 t/ha. On the other hand, a high yielding dry season rice can provide about 6-8 t/ha in about 160-165 days. Off course these are the examples of tropical climate. In general, high yielding rice variety needs relatively longer duration (140-165 days) for higher yield than short duration variety. However, genetical make up and optimum growing conditions dictate rice yield.

Dear DR JC Biswas,

Thank you so much for your answer.

1).  Combining short duration growth and high yielding is possible using rice breeding. Is that correct ?

2). If we only focus on high yielding feature, then we may get high yield varieties with a longer short duration. And if we only focus on short duration growth, we may get a lower yield variety.

Does it mean we should combine research on developing short duration and high yield varieties ?

Thanks in advance

I totally agree with DR Biswas, but I am simply extending it a little because I am not certain what you really expect. Maybe your question relates to what you decide to set as your goal. If you use yield / duration as.a selection factor you will get a different kind of outcome than if you go for one maximum duration and select for yield. Likewise would you be better off selecting for days duration or heat units? (Some climate considerations might me involved in that case.)