HETEROSIS AND COMBINING ABILITY FOR SUGAR CONTENT AND GRAIN YIELD IN SWEET AND GRAIN SORGHUM (SORGHUM BICOLOR L. MOENCH) HYBRIDS

CHAPTER ONE

INTRODUCTION

Sorghum (Sorghum bicolor L. Moench) belongs to the family Poaceae. Sorghum is the 5th most important cereal after rice, wheat, maize and barley in the world according to world sorghum production (WSP), 2017. It is grown on 40 million ha in 105 countries of Africa, Asia, Oceania and the Americas. Sorghum Production in 2017 was 63.7 million tons with the United States leading with 8.5 million metric tonnes and Nigeria is in the 2^nd position with 6.5 million metric tonnes (WSP, 2017). Sorghum grows in a wide range of temperature, high altitudes, toxic soils and tolerate drought to some extent (Richard, 1968).

Sorghum, like many grains has different uses, including human consumption and animal feed. Globally, over half of all sorghum produced in the world is used for human consumption (Ogbaga et al., 2014). It is a major crop for many poor farmers, especially in Africa, Central America, and South Asia. Grain sorghum is used for flours, porridges and side dishes, malted and distilled beverages, and specialty foods such as popped grain. Sorghum is also considered to be a significant crop for animal feeds. A more recent use of sorghum is for ethanol production. New sweet sorghum varieties are being developed for bioenergy, the ethanol being attained from the lignocellulose-rich stalks after fermentation of the sweet sorghum juice (IEA, 2013). Sweet sorghum is a water sipping, highly sustainable cropping option for producers in semi-arid regions with limited irrigation capacity or dry land producers with unpredictable rainfall.