What is a crop that requires less irrigation, but has high yield potential?

Vegetables, specifically fruit and seed veggies - you can grow them on the terrace or a small piece of land for private consumption or commercially. It demands less water to grow. Commercial production happens profitably in low rainfall areas and drought lands with efficient usage of water. Most vegetables have shallow roots, which rarely exceed 24 inches in depth. Some grow below the soil, while some grow above the soil. It's sold based on appearance and weight. These characteristics make veggies sensitive to water. Vegetable crops require around 6 inches of water in a season for radishes (below the soil crop) to 24 inches for tomatoes and watermelons (above the soil crop). Two sensitive periods are common to nearly all vegetable crops—during harvest and 2 to 3 weeks before harvest

Leaf vegetables - such as cabbage, spinach, etc. - are shallow-rooted, so it benefits from frequent irrigation throughout the season. Here the leaf growth and expansion are sensitive to water. Even though Cauliflower is not a leaf veggie, it is sensitive to water at all stages of growth. Excess water will damage the crop.
Root, tuber, and bulb vegetables - such as carrots, radishes, potatoes, and onions, yield depends on the production and translocation of carbohydrates from the leaf to the root or bulb. They require the right amount of water throughout the season. Uneven irrigation can lead to misshapen or split roots in carrots and early bulbing in onions
Fruit and seed vegetables - such as Cucumbers, watermelons, pumpkins, peas, peppers, and tomatoes are most sensitive to water stress at flowering and as fruits and seeds develop. You need to reduce irrigation as fruits and seeds mature.

These are the basics.

You can grow any veggie based on these rules for max yield.

In India, brinjal, spinach, and tomatoes are commonly grown in a terrace garden.
With a little bit of extra effort, you can grow cauliflower, ash gourd, bitter gourd, radishes, beans, fenugreek, celery, and onions.
Under professional guidance, you can also grow sapodilla, guavas, cucumbers, figs, custard apples, dragon fruits, pomegranate, papaya, Barbados, cherry, strawberries, avocado, orange, and lemon.

In the Indian climate, all you have to ensure is make sure the soil is moisturized and doesn’t get too dry. You can use mulches and spun-bonded row covers to increase temperatures for more rapid plant growth. These also can save water by reducing surface evaporation.

Control weeds. Schedule irrigation, depending on soil moisture, climate, and crop growth - apply the right amount of water at the right time.

Avoid over-irrigation - it actually damages the crop. Sorghum is a resilient crop for home gardens, demanding less irrigation compared to some others. To cultivate sorghum at home, choose a well-draining, sunny spot in your garden. Water deeply but infrequently, allowing the soil to dry slightly between watering sessions. This encourages deep root growth and reduces the need for frequent irrigation. Consider mulching around the plants to conserve soil moisture and suppress weeds. Sorghum can thrive with occasional, deep watering, making it suitable for regions with limited water resources. With proper care, your homegrown sorghum can yield a bountiful harvest while minimizing water usage.