Introduction

·       Subabul Is Widely Distributed Throughout The Tropics And Has Been Introduced Into The Philippines In The 16th Century As A Feed For Ruminant Livestock; Subsequently It Spread Throughout Asia-Pacific Region. The Plant Is Highly Valued As Ruminant Forage And As A Fuel Wood By Subsistence And Semi-Commercial Farmers Throughout South-East Asia And Parts Of Central Asia And Africa. It Is Planted In Hedgerow Systems With Grass For Cattle Production In Northern Australia, And As A Hedgerow Species In Parts Of South-East Asia And Africa. It Requires Well-Drained Soils With Ph Above 5.0. It Prefers Sub-Humid And Humid Climates Of 650–1,500 Mm And Up To 3,000 Mm Annual Rainfall And Tolerates Up To 7 Months Of Dry Season.

·       The Tree Is Extremely Tolerant To Cutting Or Grazing Once And Its Foliage Have High Nutritive Value For Ruminant Production. The Nutritional Parameters For The Edible Fraction Are 55– 70% Digestibility, 3–4.5% N, 6% Ether Extract, 6-10% Ash, 30–50% N-Free Extract, 0.8- 1.9% Ca And 0.23–0.27% P. The Foliage Is Highly Palatable To Most Grazing Animals, Especially Compared To Other Forage Tree. It Contains Mimosine, A Non-Protein Amino Acid That Has Antimitotic And Depilatory Effects On Animals. Concentrations In Young Leaf Can Be As High As 12% And The Edible Fraction Commonly Contains 4–6% Mimosine.

·       L. Leucocephala Is A Highly Self-Compatible Tetraploid (2n=4x=104) And Has A Relatively Narrow Genetic Base. It Is Thought To Have Evolved As An Amphidiploid Between L. Pulverulenta And L. Lanceolata. L. Leucocephala Hybridizes Readily With The Other Tetraploid Species L. Pallida, L. Diversifolia And L. Confertilflora And With The Diploid Species L. Esculenta, L. Retusa, L. Salvadorensis And L. Shannonii. Hybridisation With Other Diploid Species Of Leucaena Is More Difficult To Achieve. There Are Four Types Of Subabul

·       Hawaiian Type: The Plants Are Short Bushy And Remarkably Drought Tolerant. It Is Suited To Hilly Terrains In Drought Prone Areas. It Is A Prolific Seed Producer And Is Good For Fodder Purpose. K-341 Is A Hawaiian Variety.

·       Salvador Type: Tall, Tree Like And Fast Growing Having Maximum Annual Biomass Production. Possesses Large Leaves, Pods And Seeds Than Hawaiian Types. Responds To High Fertilization. Variety K-8 Is Useful For Fodder.