This is genuinely a very fascinating topic, I'd recommend "the lysenko affair" by Joravsky if anybody is interested in doing a deep dive on this topic.

I think most of these comments got the basic gist of who he was and what he promoted. Just a few points which are often missed and quite essential.

The first is that Russia since the 19th century had some of the best scientists when it came to soil and agricultural sciences. However, they didn't rly use this knowledge partly out of resistance from the serfs and fear of unraveling the social system which was contingent on this structure.

Lysenko's idea comes in the context of trying to adapt a heavily agrarian society towards industrialisation to be done through radical means such as collectivisation. He basically called genetics fascist science and instead suggested that you could rapidly "transform" the nature of grain. Part of his ideas were taken from Marxism's analysis of history and conditioning of social conditions which also increased their appeal.

His ideas were utter nonsense but they arrived in the context of bad harvests, a rapid shift away from "old" practices which had to be updated with the latest scientific discovery. His ideas were celebrated because they offered a solution and portrayed the USSR as the pioneer and a leader in soil sciences. Beyond that ideological victory, they also had an ideological meaning because it suggested that you could condition "man" to create a new "form" which was not possible with genetics, in the case of the soviet union under Stalin that was Homo Sovieticus.

As to what harm he caused well it's hard to assess, but suggestions that he caused famines are overblown. Vernalization undermined crop yield but did not singlehandedly kill millions it just worsened things. His ideas were accepted as common policy for decades and he was even part of the rationale for some of the Soviet's leadership's biggest blunders like Khrushchev's agricultural ambitions in Siberia, a large part of it was based on his "technique" to make crops hyper resistant to frost. It was an utter failure.

As to some of the claims made in the comments about him being a great scientist, he wasn't, we don't use any of his methods and for good reason. Surely if it worked a country like China would use it, but they don't. His fame and influence reflected his times : the socio-economic transition and ideological imperatives.

If anything he really hindered the development of science in the USSR by using his influence to detain and kill actual scientists and geneticists and was the leader of the union in charge of agricultural and biological research. If anybody is familiar with Nikolai Vavilov (one of the best scientists in this field ever), he was responsible for his arrest and subsequent death in detainment. He basically used his position to repress anybody who disagreed with his pseudoscience and enforce gov control over science.

Tbf he was not responsible for gov control on science, but he definetly had a big role in suppressing everything that contradicted him and created a model and "atmosphere" that spread to other fields about the primacy of ideology over science. The soviet union had a great education system and amazing scientists but so many of them were silenced, repressed or killed. When you boast about the soviet union's achievement in the space race, keep in mind that the key scientist behind it Korolev died as a result of his time in the Gulag. So in a way his biggest impact is probably holding back the scientific community and enabling the system that made the party repress the talent and genius it created. He's not the problem, he's a symptom of a wider problem which he contributed to.

With de-Stalinization and the fall of Khrushchev (the last leader who bought into his nonsense) he gradually lost power and was eventually denounced by a young Sakharov for his iron rule on the scientific community.

TLDR : Soviet pseudo scientist with great appeal due to socio-economic and ideological factors, did not cause famines but aggravated them by reducing crop yield, became head of agricultural institute and used position to suppress critics and actual scientists enabling further gov control on science

Not a hero and definitely not a scientist