Q64. Name the plant growth regulator which upon spraying on sugarcane crop, increases the length of the stem, thus increasing the yield of sugarcane crop.

2. Gibberellin

Gibberellins are another kind of promotery PGR. There are more than 100 gibberellins reported from widely different organisms such as fungi and higher plants. They are denoted as GA1, GA2, GA3 and so on.
Their ability to cause an increasein length of axis is used to increase the length of grapes stalks. Gibberellins, cause fruits like apple to elongate and improve its shape.