Susceptibility of Two Safflower (Carthamus tinctorius L) varieties to Induce Broomrapes Seed Germination, Haustorium Initiation and Radical Length

Abstract

A series of laboratory experiment was undertaken at the College of Agricultural Studies, Sudan University of Science and Technology (Weeds Research Laboratory) at Shambat in 2019 – 2020, to i) determine the reaction of two safflower varieties (Giza and Dongla) to Orobanche.crenata Forsk and Phelibanche.ramosa and their ability to sustain successful parasitism and ii) ability of air dried parts and root exudates of the safflower varieties to induce germination of the parasite. The experiments showed that safflower residues, irrespective of varieties, plant parts and amount of powder, induced both germination and haustorium initiation, Dongla leaves powder gain highest germination 64.5% compared to stem powder which gave lower germination 1.1%. Giza root powder achieved lower germination 3.7% compared toleaves and stem powder 51.33 and 15.95 respectively in O.crenata. P.ramosa affected significantly by Giza root powder which gave 61.2%, an increase in leaves powder level (10, 20 and 40 mg) showed high decreased in germination 11.32,8.8 and 9.19 % respectively. Giza and Dongla varieties, powder induced haustorium initiation and decreased radical length. Leaves powder displayed better haustorium initiation than other parts of the plant in broomrape. Giza showed high significant compared to Dongla. Root exudates results showed that Giza and Dongla varieties induced higher germination at the third week after germination and then start to be lower after fourth week after germination. Giza 7, 14, 21 and 28 days displayed 17, 22, 30, and 8 52% germination respectively, compared to Dongla which gained 22, 43.40, 28 and 35% germination at the same period respectively in O.crenata. In P.ramosa, Giza at 7, 14, 21 and 28 days displayed 12.15, 17.4, 18 and 15% germination respectively and Dongla recorded 7.42, 23.4, 18.6 and 30% germination respectively at the same period. Results showed that Giza and Dongla varieties susceptible to support germination