I am interested in using survival analysis methods on seed germination data. I have just started reading Allison's Survival analysis in SAS. Accelerated failure time analysis (using PROC LIFEREG) and Cox proportional hazards models using PROC PHREG seem promising, but I have a feeling that neither will do what I need and I may have to resort to GENMOD, GLIMMIX, or NLMIXED. The various experiments I am working on have 2-4 treatments each (e.g. 3 maternal temperatures, 4 seed germination temps, 5 genotypes, 3 seed cold stratification durations), and I'd like to know how the treatments affect the mean or median time for a seed to germinate.

I have data on seeds on petri dishes that were censused on day 1, 3, 5, 8, and 14. These are interval censored, with a seed that germinated on d8 really germinated between day 6 and day 8. LIFEREG can handle interval censoring. But seeds on the same petri dish are not independent, so I need to be able to include the dish as a random effect (often called "frailty").

Is there an approach that allows interval censoring as well as random effects? Is there a way to do this in NLMIXED or GLIMMIX? IF so , how should I modify the code below to include random effects?

PROC LIFEREG DATA=survGeno2;

CLASS geno mat_temp;

MODEL time*status(0)=geno | mat_temp;

RUN;

thanks!