Production Performance of Root Systems of Four Forage Legume Species and Their Development Characteristics in Loess Plateau,China

Production performance of four forage legumes species of Medicago sativa,Onobrychis viciifolia,Lotus corniculatus and Galega officinalis were determined,including plant height,above-ground biomass per unit area,tillers per unit area,fertile tillers per unit area,shoot /leaf ratio and fresh /dry matter weight ratio,and the distribution characteristics of their root systems in 0- 100 cm soil layers with 10 cm interval were studied. Results showed that the average aboveground fresh biomass(4 a and 5 a) of four forage legumes species successively were L. corniculatus 】 M. sativa 】 O. viciifolia 】 G. officinalis. The average plant heights in two years successively were O. viciifolia 】 M. sativa 】 G. officinalis 】 L. corniculatus. Tillers per unit area of four forage legume species in two years successively were M. sativa 】 L. corniculatus 】 O. viciifolia 】 G. officinalis. Fertile tillers per unit area in two years were O. viciifolia 】 M. sativa 】 L. corniculatus 】 G. officinalis. Average shoot /leaf ratio in two years were G. officinalis 】 M. sativa 】 O. viciifolia 】 L. corniculatus. Average moisture contents of four forage legume species in two years successively were G. officinalis 】 L. corniculatus 】 M. sativa = O. viciifolia. The distribution characteristics of root systems of four forage legumes species in 0- 100 cm soil layers were as follows: the root weights of M. sativa in 0- 40 cm soil layers accounted for about 98. 3% of total root weight,that of O. viciifolia in 0- 30 cm soil layers was 85. 8%,that of L. corniculatus in 0- 10 cm soil layers was 80%,and that of G. officinalis in 0- 40 cm soil layers was 81. 4%. The results suggested that L. corniculatus was suited to plant in slighter degraded pasture to control water and soil erosion in early stage,G. officinalis with strong lateral roots was adapted to degraded grassland in the Loess Plateau where soil nutrient was poor,while O. viciifolia and M. sativa with potentially strong main root were fit for water and soil conservation in the losses plateau for long term.

Tetrazolium Test to Evaluate Stizolobium aterrimum Seeds Quality

The purpose of this study was to verify the efficiency of methods of pre-conditioning and concentrations of tetrazolium solution in the evaluation of physiological quality of Stizolobium aterrimum seeds. Commercial seeds have passed through the process of accelerated aging for composing lots of 0, 24, 48, 96 and 144 hours, and were submitted to the pre-conditioning: 1) Scarification with sandpaper number 100 and immersion in water at room temperature for 18 hours, 2) Immersion in water at 95°C and maintained in the same water outside the heating at 25°C for 18 hours. After preconditioning, the seed coats were removed and immersed in embryos tetrazolium salt at 0.25%, 0.5% and 1% for 150 minutes and maintained in the dark at 25°C for color development. To compare the results obtained in the tetrazolium test, we performed germination test, first counting and germination speed index. The method of scarification with sandpaper and later soaked in water for 18 hours at 25°C, the most efficient way in preconditioning of seeds of Stizolobium aterrimum and concentration of 1.0% tetrazolium solution for 150 minutes at 25°C, allows evaluating the quality of seed lots from this species.

Application of CRISPR/Cas9 technology in forages

Genome editing is an advanced genetic modification tool that facilitates the removal,insertion,or substitution of nucleotides in the genome of an organism for mutation induction.CRISPR/Cas9(clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9)is the most widely used genome editing tool that can precisely modify the specific sequence of a genome.Significant progress has been made in the use of CRISPR/Cas9 for the genetic improvement of food crops.However,in forage crops,the use of CRISPR/Cas9 is still in the infant stage with limited understanding and application.This article reviews current advances in the establishment and application of the CRISPR/Cas9 system in alfalfa,summarizes the application of CRISPR/Cas9 in several other forage legume and grass species,and discusses the prospects of CRISPR/Cas9 in the genetic improvement of forage crops.