TY - JOUR
T1 - Morphology of Malaysian Weedy Rice (Oryza sativa)
T2 - Diversity, Origin and Implications for Weed Management
AU - Sudianto, Edi
AU - Neik, Ting Xiang
AU - Tam, Sheh May
AU - Chuah, Tse Seng
AU - Idris, Akmal Adilah
AU - Olsen, Kenneth M.
AU - Song, Beng Kah
PY - 2016/7/1
Y1 - 2016/7/1
N2 - Weedy rice is one of the most dominant and competitive weed species found throughout rice planting areas worldwide. In Malaysia, a combination of agricultural practices such as direct seeding and shared use of machinery has contributed to the rapid proliferation of weedy rice across paddy fields in recent decades. Here, we report on the morphological characterization of weedy rice populations and inferred origin(s) of different morphotypes present in Peninsular Malaysia. Eight weedy rice morphotypes were distinguished based on a combination of traits such as awn presence/absence and hull color, from 193 accessions collected in 17 locations. Results showed a high proportion of awnless accessions (strawhull-, intermediate strawhull-, and brownhull-colored morphotypes, together composing 65% of sampled accessions), with awned accessions represented by strawhull, brownhull, and blackhull forms. Clustering and PCA analyses revealed four major clusters: (1) O. rufipogon and the majority of awned, blackhull, and brownhull-suggestive of a type of weedy rice originating from wild Oryza populations; (2) elite indica cultivar rice and the majority of strawhull weeds-supporting a previous proposal that weedy rice from Malaysia mainly evolved from indirect selection on cultivars for easy-shattering feral forms; (3) the majority of brownhull; and (4) a mixture of other weedy morphotypes-potentially reflecting multiple origins and subsequent admixture. The combination of key morphological descriptors will be useful for advising farmers appropriately in strategies for controlling the spread of weedy rice, including periodic manual weeding to reduce buildup of the seed bank in the fields. Nomenclature: Weedy rice, Oryza sativa L. ORYSA; rice cultivars, Oryza sativa L. ssp. indica S. Kato ORYSA; wild rice, Oryza rufipogon Griffiths.
AB - Weedy rice is one of the most dominant and competitive weed species found throughout rice planting areas worldwide. In Malaysia, a combination of agricultural practices such as direct seeding and shared use of machinery has contributed to the rapid proliferation of weedy rice across paddy fields in recent decades. Here, we report on the morphological characterization of weedy rice populations and inferred origin(s) of different morphotypes present in Peninsular Malaysia. Eight weedy rice morphotypes were distinguished based on a combination of traits such as awn presence/absence and hull color, from 193 accessions collected in 17 locations. Results showed a high proportion of awnless accessions (strawhull-, intermediate strawhull-, and brownhull-colored morphotypes, together composing 65% of sampled accessions), with awned accessions represented by strawhull, brownhull, and blackhull forms. Clustering and PCA analyses revealed four major clusters: (1) O. rufipogon and the majority of awned, blackhull, and brownhull-suggestive of a type of weedy rice originating from wild Oryza populations; (2) elite indica cultivar rice and the majority of strawhull weeds-supporting a previous proposal that weedy rice from Malaysia mainly evolved from indirect selection on cultivars for easy-shattering feral forms; (3) the majority of brownhull; and (4) a mixture of other weedy morphotypes-potentially reflecting multiple origins and subsequent admixture. The combination of key morphological descriptors will be useful for advising farmers appropriately in strategies for controlling the spread of weedy rice, including periodic manual weeding to reduce buildup of the seed bank in the fields. Nomenclature: Weedy rice, Oryza sativa L. ORYSA; rice cultivars, Oryza sativa L. ssp. indica S. Kato ORYSA; wild rice, Oryza rufipogon Griffiths.
KW - Morphological characterization
KW - rice
KW - seed traits
KW - weed control
KW - weedy rice
UR - http://www.scopus.com/inward/record.url?scp=84979536557&partnerID=8YFLogxK
U2 - 10.1614/WS-D-15-00168.1
DO - 10.1614/WS-D-15-00168.1
M3 - Article
AN - SCOPUS:84979536557
SN - 0043-1745
VL - 64
SP - 501
EP - 512
JO - Weed Science
JF - Weed Science
IS - 3
ER -