Days to anthesis - Computation

Number of days from sowing to when 50% of the plants shed pollen. Observe a known number of plants carefully (guideline: N = 20 for inbred lines or hybrids; N = 35 for open pollinated varieties) at the same time each day until 50% of the plants in the plot have produced at least one visible anther and score the number of days from sowing. Also, it can be calculated using sowing and anthesis date.