Seed Germination Ecology of Itchgrass (Rottboellia cochinchinensis)

Abstract

Itchgrass is a weed of many crops throughout the tropics and one of the most important grass weeds of rainfed rice. Experiments were conducted in the laboratory and screenhouse to determine the effects of light, alternating day/night temperatures, high temperature pretreatment, water stress, seed burial depth, and rice residue on seed germination and seedling emergence of itchgrass in the Philippines. Two populations were evaluated and the results were consistent for both populations. Germination in the light/dark regime was greater at alternating day/night temperatures of 25/15 C than at 35/25, 30/20, or 20/10 C. Light was not a requirement for germination, but a light/dark regime increased germination by 96%, across temperature and population. A 5-min high temperature pretreatment for 50% inhibition of maximum itchgrass germination ranged from 145 to 151 C with no germination when seeds were exposed to ≥ 180 C. The osmotic potential required for 50% inhibition of maximum germination was −0.6 MPa for itchgrass, although some seeds germinated at −0.8 MPa. Seedling emergence was greatest for seeds placed on the soil surface, and emergence declined with increasing soil burial depth; no seedlings emerged from seeds buried at 10 cm. The addition of rice residue to soil surface in pots at rates equivalent to 4 to 6 Mg ha−1reduced itchgrass seedling emergence. Since seedling emergence was greatest at shallow depths and germination was stimulated by light, itchgrass may become a problem in systems where soil is cultivated at shallow depths. Knowledge gained in this study could contribute to developing components of integrated weed management strategies for itchgrass.

Predicting Seed Germination of Safflower (Carthamus Tinctorius) Cultivars Using Hydrotime Model

“…The interactive effect of water potential on germination rate and percentage of safflower has also been reported in other species (Kebreab and Murdoch, 1999;Ebrahimi and Eslami 2012;Nandula et al, 2006;Bolfrey-Arku et al, 2011).…”

Disentangling plant establishment in sandy coastal systems: biotic and abiotic factors that determine Allagoptera arenaria (Arecaceae) germination

“…The ability to germinate under environmental constraints gives a species the chance to become established in a community (Bolfrey-Arku et al 2011). In contrast to species unable to stand high temperatures and low water availability (Fialho & Furtado 1993;Pinheiro & Borghetti 2003;Mantovani & Iglesias 2008), some restinga species establish in open, sandy sites (Zaluar & Scarano 2000;Scarano 2002) and often act as facilitators of other plant species (Scarano 2002;Scarano et al 2004).…”

Molecular Basis for Resistance to Fluazifop-P-Butyl in Itchgrass (Rottboellia cochinchinensis) from Costa Rica

“…The first name refers to its fiberglass-like hairs on the sheaths and leaves that can cause severe skin irritation and infection on animals and humans, whereas the last name refers to its capacity to invade and progress into new areas (Valverde, 2004;Silva et al, 2009;Bolfrey-Arku et al, 2011). Itchgrass is native to India, but it is now present in more than 30 warm-climate countries of America, Africa, Asia and Oceania, and has become a major and troublesome weed in several annual crops including beans, cassava, cotton, maize, peanut, pineapple, sorghum, sugar cane, upland and rain-fed rice, and perennial crops such as banana, citrus, mango and oil palm at early growth stages (Bolfrey-Arku et al, 2011). Valverde (2004) has estimated that more than 3.5 million ha of crop areas are infested with itchgrass in Central America and the Caribbean alone, with crop yield losses up to 80-100% being reported in both tropical and subtropical conditions (Valverde, 2004;Bolfrey-Arku et al, 2011).…”

“…Itchgrass is native to India, but it is now present in more than 30 warm-climate countries of America, Africa, Asia and Oceania, and has become a major and troublesome weed in several annual crops including beans, cassava, cotton, maize, peanut, pineapple, sorghum, sugar cane, upland and rain-fed rice, and perennial crops such as banana, citrus, mango and oil palm at early growth stages (Bolfrey-Arku et al, 2011). Valverde (2004) has estimated that more than 3.5 million ha of crop areas are infested with itchgrass in Central America and the Caribbean alone, with crop yield losses up to 80-100% being reported in both tropical and subtropical conditions (Valverde, 2004;Bolfrey-Arku et al, 2011). In addition, the presence of itchgrass seeds in exported crop containers might result in rejection due to quarantine restrictions, leading to substantial economical losses for growers (García Fernández, 2007).…”