ESL Interpretation : The right marker for genotyping tasks !
These technical concerns are also detailed in
Loudet, Chaillou, Camilleri, Bouchez and Daniel-Vedele, 2002. Bay-0 x Shahdara recombinant inbred lines population: a powerful tool for the genetic dissection of complex traits in Arabidopsis. Theoretical and Applied Genetics, vol 104 (6-7), pp 1173-1184 
The ESL code is designed to avoid some of the main problems in genotyping, especially in medium-throughput genotyping:
E => unbalanced amplification efficiency between the ecotypes is a problem, particularly to detect heterozygotes which could be misinterpreted as homozygous
S => unspecific additional bands usually make genotype reading difficult and sometimes cause efficiency problems
L => on 3% Agarose gel with thin combs (0.75 mm) and fragments in the 150-250 bp range, one may not be able to distinguish between bands differing by less than 10 bp (or even more), with a high level of confidence.
In any case, true heterozygote DNA should be tested before and in each PCR plate to ensure the correct reading of this particular genotype (as it could be affected by all these factors : PCR efficiency, unspecific bands and length difference between alleles).
PCR : PCR Conditions [MgCl2] 1.5 mM
[dNTPs] 60 µM
[Primers] 0.8 µM each
PCR program 94° 2 min
94° 15 sec
Touchdown 54-50° 15 sec 8 cycles with -0.5° / cycle from 54° to 50°, then 35 cycles at 50°
72° 30 sec
72° 2 min
Electrophoresis : 3% Agarose gel