Rice genotypes varies in their response to AMF inoculation for physiological traits like shoot growth and root growth and also nutrient demand. 8 rice varieties such as Black Gora (V1), ARC 12737 (V2), Yamuk (V3), Jinghasal (V4), Dular (V5), TN1 (V6), MTU 7029 (V7) & IR 64 (V8) were considered for the study. Varieties V1, V2 & V3, are the slow growing land race selections showed negative or marginal positive response to AMF inoculation at early stage having higher shoot P concentration & total plant P content. There was a gain in P concentration and also content in all the varieties due to AMF inoculation. However, the incremental rise is higher in V4, V6, V7 & V8, the fast growing high yielding varieties than that of traditional land race varieties. Varieties V5 is an exception that it behaved like intermediate between the two variety groups. The inherent difference for root P concentration and total P content among the varieties are not so significant but the gain in P due to mycorrhization is observed in all the varieties and the magnitude of increase between the variety groups are almost equal. However, a trend of higher increase is found in positively responding fast growing varieties. The response pattern for all the varieties are almost similar at both 15 & 30 days of the plant growth. When P-acquisition response were analyzed, the fast growing modern varieties showed a higher response for both the traits of plant growth and whole P content due to AMF inoculation and thus have a higher P uptake than that of slow growing land race varieties. The traditional varieties, in spite of gaining P-acquisition are not reflected in their plant growth due to possible AMF infection rather, a negative response in plant growth is observed at the early stage of plant growth. It also revealed that the whole P uptake might not utilized or needed for growth at early stage. Analysis of the possible translocation of incremental P due to mycorrhization showed a characteristic difference where traditional land race varieties partitioned in 60:40 proportions compared to fast growing varieties that partitioned to nearly 50:50 proportion between root & shoot. For all the varieties, the proportional P gain in shoot is increases at the later age, although the magnitude of increase is highest in fast growing high P demanding varieties. The variety Dular (V5) although showed a equal P-uptake response to that of fast growing varieties but did not reflect to the corresponding shoot growth as in case of fast growing varieties.
Mycorrhization, concentration, p-acquisition
