W hen Jhon Edison Ccoyo Ccana looks up into the overarching inky-dark Andean night sky above him, pierced only with distant twinkly stars, he's searching for a sign: the constellation known in Peru as the Inca Cross. In the native Quechua language, it's called Chacana , and when it's seen leaning on its side, he knows it's time to start harvesting the vast indigenous potato crop. Knowledge of this pivotal celestial indicator has been passed down through generations and is rooted in ancestral agricultural techniques, tools and knowledge. Here, the connection to Panchamama , mother earth, is the backbone of all life; farming is inseparable from identity. I'm 3,250m above sea level in the Andean mountains at Parque de la Papa (Quechua for 'Potato Park'), in the village of Chahuaytire, 30 miles northeast of the historic city of Cusco, to meet the indigenous custodians who are conserving the humble potato for climate resilience.…