Hybrid Seed Rows & Female:Male & Seed Yield
Plans maize
Enter the female:male planting ratio, plot area and seed yield per hectare to get the female fraction, seed-parent area and saleable hybrid seed yield — so you plan a production plot that hits target.
Plan your seed plot
Next: only the 66.7% female rows (0.3 ha) set harvestable hybrid seed — plan a 4:2 pattern and stagger male sowing so pollen sheds over the female flowering window.
Male rows pollinate but are detasseled/discarded for seed; tighter ratios raise female fraction but can starve pollen supply. Yields vary by crop, isolation and detasseling discipline.
Hybrid seed rows — key facts
- Female fraction
- female ÷ (female + male) rows
- Female area
- fraction × plot area
- Seed yield
- female area × yield per ha
- Female rows
- seed parent — sets the seed
- Male rows
- pollen parent — pollen only
- Common ratios
- 4:2, 6:2 (≈67–75% female)
- Isolation
- blocks stray contaminant pollen
- Privacy
- Runs in your browser; nothing uploaded
Only the female rows earn — design the plot around that
Hybrid seed production plants two parents side by side: female (seed) rows that are emasculated or male-sterile, and male (pollen) rows that fertilise them. They go in a set ratio — 4:2, 6:2 and so on — and only the female rows set the hybrid seed you harvest and sell. So the female fraction and the area it covers drive the whole plot's seed yield, while the male rows are pure pollen overhead. Get the ratio right and you maximise saleable seed without starving the female rows of pollen.
This tool gives the female:male ratio, female fraction, seed-parent area and expected hybrid seed yield from your ratio, plot area and yield per hectare. Use it to size a plot for a target quantity, compare ratios, and plan the crossing block — then keep the isolation distance to protect purity. Pair it with the Seed Rate, Plant Spacing & Population and Seed Germination Test tools for a full seed plan.
Size the plot
Plant enough female area to hit your target.
Compare ratios
See how 4:2 vs 6:2 changes seed yield.
Maximise saleable seed
Lift the female fraction without losing pollination.
Protect purity
Keep isolation distance from stray pollen.
Frequently Asked Questions
What is a hybrid seed row ratio?+
In hybrid seed production you plant female (seed parent) and male (pollen parent) rows in a fixed pattern — for example 4:2 or 6:2, meaning four or six female rows for every two male rows. Only the female rows are pollinated by the male and set the saleable hybrid seed; the male rows just supply pollen. The ratio decides how much of the plot earns seed.
How is the seed yield calculated?+
First find the female fraction = female rows ÷ (female rows + male rows). Multiply that by the plot area to get the female (seed-parent) area, then multiply by the seed yield per hectare. For example a 6:2 plot is 75% female; on 2 ha that's 1.5 ha of seed parent, and at 1500 kg/ha it yields about 2250 kg of hybrid seed.
Why do only the female rows yield seed?+
The female (seed) parent is emasculated or male-sterile, so it cannot self-pollinate. It receives pollen from the adjacent male rows and sets the hybrid seed, which is harvested and sold. The male rows contribute pollen only and are usually discarded after flowering, so they do not count toward saleable seed yield.
What ratios are commonly used?+
Common female:male ratios run from 2:1 up to 8:2 or higher, depending on the crop, how far pollen travels and pollen load of the male. Wider ratios (more female rows per male row) raise the female fraction and seed yield but risk poor pollination of the outer female rows. Crops with abundant, mobile pollen tolerate wider ratios.
What is the female fraction and why does it matter?+
The female fraction is the share of total rows that are seed-parent rows. It directly scales the seed yield: a higher female fraction puts more of the plot into saleable seed. A 4:2 plot is 67% female; a 6:2 plot is 75%. Balancing a high female fraction against reliable pollination is the core trade-off of plot design.
What is isolation distance and why is it needed?+
Isolation distance is the gap kept between a hybrid seed plot and any other compatible crop or variety, so stray (contaminant) pollen cannot fertilise the female rows and lower genetic purity. Distances vary by crop and certification class — often a few hundred metres for cross-pollinated species. It protects the hybridity of the seed you sell.
How do I find the seed yield per hectare?+
Use the seed-parent yield expected for your crop, hybrid and management — not the grain yield of a commercial field, which is usually higher. Seed crops are managed for quality and purity, so per-hectare seed yields are often lower. Use your own plot records or recommended figures from the breeder or seed company.
Can it size a plot for a target quantity?+
Yes — work backwards. If you need a certain quantity of hybrid seed, divide it by the seed yield per hectare to get the female area, then divide by the female fraction to get the total plot area to plant. The tool's female fraction and seed yield outputs make that planning straightforward.
Does this work for any crop or area unit?+
Yes — it works for maize, sunflower, sorghum, rice, vegetables or any crop grown as a female:male production plot. Enter the ratio, area in acres, hectares, bigha, guntha or m², and the seed yield per hectare. The row-ratio approach to seed production is universal.
Are the figures precise?+
They're solid planning figures. Real seed yield varies with pollination success, weather at flowering, nicking (synchrony of female and male flowering), rogueing and harvest losses. Use the numbers to design the plot and set expectations, then adjust against your own production records season by season.