Document Title: Breeding perennial, importance of breeding perennial crops, challenges of breeding perennial crops

Paper code: 13087

Breeding perennial, importance of breeding perennial crops, challenges of breeding perennial crops

Question

In some parts of the world, breeding efforts have been made to establish perennial grains which have traditionally been annual crops eg perennial rice in Australia and perennial wheat in Asia.

Provide a brief write-up on the current status (October 2019)of the advances in establishing in establishing perennial grains rice and wheat(12marks)

Explain any 10 reasons why such initiatives to establish perennial grains are very important(10marks)

Describe any 5 challenges(in both lab and field ) that such breeding programs for perennial rice/ wheat encounter

Introduction

Perennial crops, growing in mixtures, make up most of the world's natural terrestrial biomes. In contrast, monocultures of annual crops are sown on more than two-thirds of global cropland. Grain and oilseed crops are the foundation of the human diet, but to date there are no perennial species that produce adequate grain harvests. Yet perennial plant communities store more carbon, maintain better soil and water quality, and manage nutrients more conservatively than do annual plant communities, and they have greater biomass and resource management capacity. These advantages provide a base from which to begin hybridization and selection for increased resource allocation to developing seeds, a decades-long process that must overcome or circumvent genetic complications. Breeding programs aimed at developing perennial grain crops have been initiated in wheat, sorghum, sunflower, intermediate wheatgrass, and other species.

a)

Current work on intermediate wheatgrass exemplifies direct domestication, and breeding programs in perennial wheat, sorghum, and sunflower illustrate the wide hybridization approach.

There is good evidence that humans began consuming the seeds of numerous wild grasses over 23,000 years BP and some evidence that our consumption of cereals began over 100,000 years ago. The relationship between humans and cereals gradually transitioned from facultative to obligate with the domestication of annual grass species, including rice, wheat, barley, maize, millet, and sorghum, in at least six centers of origin around the world 5–10,000 years BP . In addition to grass seeds, pulses or seed-crop legumes such as beans or lentils were also domesticated in the same major centers of crop domestication. With domestication, the symbiosis between humans and annual cereal, pulse, and oilseed crops, or collectively grains, became spectacularly successful.